I know parts for it are hard to come by, particularly any sort of performance upgrades but if you can get the Ford FMX to handle 500+ HP why can't the M12 do the same given their shared heritage? Surely for a mild performance street/strip engine, mine is closer to 350HP, the M12 or maybe even the M11 should be more than adequate and avoid the additional work and expense of swapping over to one of the other two.

Although I cant prove it just yet I believe the m11 and m12 are basically the same trans. A m12 has more clutches than a m11, making it a heavier duty transmission. From going through some parts books I have and comparing part numbers for fmx and m12 transmissions there are clutch parts and bands from various fmx years that interchange with m12 parts. Yes there are some performance clutches and bands avalable for fmx transmissions. As far as valve body mods the first thing I would do is make sure the transmission is running the max line pressure it should have or maybe a little more. From what I can see the converter hub is a weak area also, I have read that a ford hub can be put on the amc converter allowing one to use a fmx pump on a m12.

 

http://www.australianjavelins.com/media/toughening_borg_warner_m11_m12.pdf" rel="nofollow - http://www.australianjavelins.com/media/toughening_borg_warner_m11_m12.pdf

 

This covers the issue with the convertor snout weakness, too much lash, and B&M's solution to fixing it.

 

I'm in the process of pulling the M11 out of my car and will them be able to do some direct comparisons with the M12 I have here that I stripped down the other day.

 

The second tranny has 12-1 cast into the top of the case, can't read the tag so don't know what is on it but it has two bolts holding the front band servo so this should be the M12.

 

Both have 28 spline output shaft.

 

Besides the number of bolts holding the front servo I can't really see any other internal difference, same diameter and number of friction and steel clutches in each, same band diameter and width.

 

I'm not sure what to think now.

 

Did a bit of measuring and counting, the clutches are more or less the same as those in the Ford FMX.

Thanks for the great info Rick.

 

Seems like parts for the FMX are even getting hard to find these days.

 

This is about all I could find in the way of clutch frictions and steel plates.

 

 

I haven't seen any rebuild kits specifically listed for the M12, they all have the application as M11/11B/12 so one would hope there are extra bits in there to cover any differences between them.

 

In my case what I have is a M11 that has toasted the front band and scored the drum and a M12 that has been laying around in somebody's paddock for years and has a bit of water damage in a few places. Plan of attack would be to do a rebuild using the case, servos and front drum from the M12 and probably everything else from the M11 if that would work? The M11 is from a console shift car and the M12 has the shift lever pointing down so I'm assuming it's from a column shift car. I believe the valve body from the floor shift car would be the one to use because it allows more manual control of the shifting aka the "Shift Command" feature. I don’t know if there are and differences between the M11 and M12 valve bodies that would work against this?

 

Hopefully when I get the engine and diff sorted I can crack into the 12’s that would be the plan.

 

Going a little bit of the rebuild side of things the only other thing on my mind is if I can use something other than the factory dipstick tube, which is a real pain with headers? Maybe drill the case to take a Lokar setup of some sort?

 

I deleted this comment, to remain polite to Farna.

I have no burning desire to embarrass anyone here on AMC Forum.

Thank you for your insightful understanding.

 

 

 

 

 

 

 

Borg Warner M11

 

 

 

 

Tell me more about the tranny pan/dipstick mod. What did you do? We cut a piece out of the elbow to tighten the angle. It helped, but is still right against the collector of my Super Comps for about 4". Now my tube is beginning to seep where we made the weld on the tube. Theres got to be a better way.

 

Thanks,

Jack

 

 

Covers the torque convertor, improved friction materials and increasing the line pressure but there is mention of other valve body mods that they have chosen to keep secret, after all B&M wanted you to buy their products.

 

Any idea on the price of a convertor from Continental? I can get my factory one "improved" locally but it seems a smaller one might be a better option.

 

This is what I did with my dipstick tube:

 

 

But in the end it still wound up hard against the collector so it would be nice to find a better solution.

 

I did add a bit of insulating sleeve to try to minimise heat transfer:

 

 

 

 _________________________________________________________________________

 

I got mine from Contenental about a month or two back WesternRed. It was built special for me with the built 390, 3.54 gears, and 26-1/2" tall tires. It was $717.00 shipped to the house. Nice people to work with. I talked to Peter. Great, helpful guy...

I deleted my long comment here to save space on AMC Forum ...to be 'nice'.

I must have said something about 'bronze frictions' since they are alluded to in the next comment.

As I understand it now, based upon many years of study, since I first began rebuilding these units back in the mid-nineties, the bronze frictions are basically become a 'thing of the past' because...

1) EPA rules and regulations have 'put the squeeze on' many metal manufacturing businesses for the amount of 'run off' toxic waste in our public water systems.

2) Copper is directed by the artful use of law, into the production of 'high tech electronic appliances'. (where 'law' is essentially the same as 'EPA rules and regulations' ...which are enforced, as if, they are 'real' laws!) (but the are not: they are 'rules and regulations' made by employees, not actually by our elected officials who hold office and have the authority to pass bills and make real laws!)

Wherefore, copper is become higher in status due to the government action to increase the 'high tech industry'. (for more products to sell, to more people, to collect more taxes, to become more wealthy, to rule the world etc etc!)

The government is in the business of 'economic stimulation'.

They are doing their best to do a similar thing with every other commodity, like 'plastics' (petro-chemical industry; major source for plastic is natural gas)

In so many words, this is the reason we see bronze lined friction plates fade into oblivion.

-The whole world needs copper wiring to cover the earth with electrical products instead.

----------------------------------------------------------------------------------------------

Anyway, back at the ranch...

Why do I say 'bronze frictions are good'? (I've studied this topic for at least twenty years)

1) Bronze lined clutch friction plates offer the best heat transfer; plate to plate, within the clutch drum assembly. -Where any other type of material works more as an insulator instead/works against heat transfer, not transferring heat out of the friction plate nearly as well. -where excessive heat is the enemy of any automatic transmission.

2) Information broadcast from the makers of bronze bushings clearly insist that bronze-to-steel is among the very best, most durable combination to resist wear -having a very low 'coefficent of drag' when bronze is used for bearing surface on steel. Hence, a bronze friction plate will last longer than most any other material -where the plates 'rub' on steel drive plates inside the clutch assembly.

Note: Friction plates, inside the automatic transmission, can be conceptualized in analogy to them being like 'brake shoes' = they are like the 'disk brakes' on your car; they 'grab and release' by hydraulic action very similar to 'disc brake pads' -Note: High performance disc brake shoes are called 'semi-metallic' = flakes of metal are added to the friction lining on the brake pads to improve the heat transfer, in order to reduce 'brake fade'.

-Hence, the analogy is altogether insightful: bronze frictions (are the obvious superior choice to) reduce 'brake fade' inside the clutch assembly, by offering superior heat transfer capacity.

-they'll last longer, and the transmission will run cooler.

The argument against running bronze frictions:

When they wear, they shed micro metallic particles into the ATF & those tiny particles can interfere with the smooth operation of the unit's precision made hydraulic valve mechnaisms (in the 'valve body')

-but 'paper' frictions don't...

...however, the particles of 'paper' must go somewhere: they don't just vaporize; they go into the ATF also, adding a trace amount of insulative/non-heat transfer properites into the oil mixture...

The same concepts apply to (pun intended) any other type of brake shoe material: where does the 'off-scouring' go? It's absorbed into the ATF, in an auto trans-brake application.

Note: The same can be said for the 'bands': they are just like 'band brakes' on a go-cart (they are 'band brakes' in reality, inside the transmission though)

-The 'ATF' is basically hydraulic fluid dyed red for automotive application (highly complex chemistry of modern auto trans fluid additives and composition is another technical discussion)

Side note; GM's Hydromatic first used 'whale oil' for it's hydraulic fluid ...and whale oil, was used for 'lamp oil' and this is why the GM Hydromatic factory fire was so horrific; whale oil is very flammable -why it was used for lamp oil. In fact, around mid-fifties, 'Type A' was basically whale oil dyed red, while the petro-chemical industry learned to make the same type of fluid from 'crude oil' by refining processes. (I think I said that right/close enough I guess)

SO that's basically 'it' in a nutshell: Think of the clutch frictions and steels as if they are disc brakes, but in a fluid bath of ATF.

Where car makers make millions of cars, instead of millions of transmissions using bronze frictions, that same amount of copper content has gone into the 'high tech industry' instead.

 

Hopefully the re-lining is under control, just need to sort out the rest of the rebuild to improve it's chances of survival in the future.

 

The aussie distirbutor for Alto has both the fixed and mobile phones disconnected so that is not a good sign.

 

As far as the brass ones go the only brass lined clutches I can find are for Borg Warner Velvet Drive marine transmissions.

 

Anyway got my bands back yesterday so things are starting to move:

 

Look up Carroll Shelby and Ford . And from what I have read  Borg Warner Did All their own research with the help of may racing teams over many years  
http://en.wikipedia.org/wiki/BorgWarner" rel="nofollow - http://en.wikipedia.org/wiki/BorgWarner

There can be no back and forth 'slack' in the engagement because the engine only turns one direction! Hence, the transmission's oil pump is only driven in one direction!*

When we downshift the transmission, that does not place force on the oil pump drive; that transfers force through the input shaft into the torque converter (NOT the oil pump drive mechanism)

Performance steels, clutches and bands generally last longer, especially if the trans has been reprogrammed to shift firmer. Auto trannys are programmed from the factory to slip a bit between gear shifts. This makes for a nice smooth and light shift. They will shift a bit harder as you speed up -- the vacuum modulator or TV cable controls internal pressure, so there is more pressure as there is more load placed on the trans. That can be adjusted to firm up the shifts a little, but you can only do so much there. On the BW design you can shim the shift accumulators so that they "hit" the servos and clutches a bit harder. This can be done with washers -- one or two under each accumulator spring. You may have to pull the valve body a couple times before you figure out how much shimming is good for you.

Note that performance bands can wear the surface of the drum more since they are a bit more aggressive than stock. Any extra wear should be minimal, but it's there. Same with the clutches, but the steels between the clutches take a lot of the extra wear, so not as noticeable in the clutch packs. Using good trans fluid and keeping it cool minimizes wear. The cooler in the bottom of the radiator isn't enough! Even a small cooler added inline with the built in radiator cooler works wonders! I always run through the radiator cooler then the added cooler, or skip the radiator mounted cooler altogether (with a medium or large external cooler).

rsrguy3 wrote: What's the most recent m12 rebuild anyone here has done? Would you have a solid up to date list of currently available parts and suppliers (a-z) friction, steels, gaskets etc. So far I'm lost at sea. Also what difference to wear and drivability do high performance parts make? Steels, bronz that sort of stuff?

https://www.transpartsonline.com/TRANS_PARTS_FILE/tpcat.php?TransPartsOnline=BW12&TransPartsType=BW12" rel="nofollow - https://www.transpartsonline.com/TRANS_PARTS_FILE/tpcat.php?TransPartsOnline=BW12&TransPartsType=BW12

This is why this is such a cool hobby/ lifestyle, guys like Gary and those of you here on the forum, willing to share. It's a huge deal.. for me any way. I've been away from performance street rods for a long time now, it appears I've forgotten almost everything I'd learned. I just hope you guys from my dad and Gary's generation do the best you can to look after yourselves. I for one don't take your influence and guidance for granted.

Thank you guys! 

I'm not trying to embarrass anyone here for conveying a false historical record.

Mythomania is compulsive lying, which damages the reputation of our favorite American Motors products.

We don't need to make up new lies to cover up the old lies; that is mythomania, which is a mental illness.

-------------------------------------------------------------------------------------------------------------

That is correct: I have personally done much research to find an actual AMC specific 'shift kit' for our old AM Warner Gear iron case automatic transmissions.

If I could find it, I would post a link on XRV8 Race Parts website.

-if only to reduce the 'stigma factor' that says 'no; you can't hop up that transmission'.

However, what I have found is a handful of springs, in a kit for Ford Cruise-O-Matic, which looks just like the springs that are used in the AM Warner Gear Flash-O-Matic and Shift Command units.

Yes: The main pump spring for all these units appears to be identical, and the kits for Ford units typically include a 'higher performance spring' for the (front) pump.

-Presumably to increase pump pressure, to increase line pressure, to increase lubrication circuit pressure and overall flow rate ...presumably for increased cooling by increased fluid flow, which doubles as a carrier of heat to the cooling system.

The thing about this is, increasing pump pressure, increases parasitic loss by making the pump work harder.

And having a lower parasitic loss rating is one of the better, more desirable features of running a Shift Command unit. (Like FMX, Shift Commands have no rear pump) (the earlier Ford-O-Matic, Cruise-O-Matic and Flash-O-Matic units have a rear pump in order to push start the car! -something that faded away through the evolution of more dependable electrical charging systems/the alternator, replacing the older generator systems)

I'm still working on this aspect, but from my perspective, what I would like to learn is how to restrict pressure (or reduce pressure) to the 'reverse circuit' -to prevent a 'reverse clunk' on a higher rpm (hopped up) idle type engine.

(my Rambler V8 idles at about 1000 rpm with it's custom made independent runner intake system, and it makes a hard 'clunk' when shifted into reverse: if I adjust my line pressure higher to get firm/hard shifts, then the reverse makes a more severe 'clunk' and vise-versa)

I have the links to Alto parts, with some of the associated information on my XRV8 Race Parts website.

One of the reasons why I keep them posted there, is to keep them 'separated' from the usual bulloney type information: I can control the text on my pages, but I can't control the random sayings other people post on other websites...

I'm less interested in disputing myths, than I am interested in simply posting good hop up information.

-In order to (hopefully) do my part to repair the damage done to the reputation of our favorite cars.

---------------------------------------------------------------------------------------------------------

That said, concerning this discussion named 'Borg Warner M12 for performance' here on AMC Forum:

1) The highest high performance example AMCers have for this unit is '67 Grant Rebel SST Funny Car.

-This was a 343 bored and stroked to 430 CID, supercharged, set up to burn alcohol and is said to have made 1000+ HP.

-None of the vintage literature contains any statement about transmission failure (!)

-IF there ever was a problem with the auto trans, surely the mainstream writers would have jumped on it and smeared the transmission, to blame something... -so typical. But no; did not happen.

Some of the vintage literature clearly states that AMC desired Grant Industries to use the original AM Shift Command unit that came with the 343 engine for the racing effort.

That means, the unit would have been an AM Warner Gear Model 11B unit.

-------------------------------------------------------------------------------

What is the difference between AMWG M11B and AMWG M12?

The only two differences I know of are:

1) The M12 uses one more friction plate to make both clutches contain five friction disks.

2) The M12 uses a 'two bolt front servo' to operate the front band vs. all other AM versions using a 'one bolt servo' for the same purpose.

(the M11B is a 'four and five' unit, the M10B is a 'four and four' unit and they both have the 'one bolt front servo' -for comparison)

(M10B unit was used behind sixties era Rambler 327 V8 aka 'Flash-O-Matic')

So... essentially, the M12 is 'the hoss' of all AM Warner Gear iron case automatic transmissions.

-It's the 'biggest-baddest' one of them all, made to cope with more torque in a heavier car than any other version (of the same basic unit)

Lots of info on these previous posts if you search that number.

OK, good, I'll research that pn# -thank you.

---------------------------------------------

As I understand it, I would like to explain a few general concepts that helps me to understand how automatic transmissions work.

And, in theory, when we understand the basic operating principals, it takes some of the mystery out, and reduces 'fear of unknown' ...where knowledge of how they operate is considered to be a 'black art' -something 'magical' or 'too risky' for an average person to deal with.

With exception of all electronically assisted 'new school' automatic transmissions, an automatic transmission like these (Ford-O-Matic, Cruise-O-Matic, FMX, Flash-O-Matic and Shift Command) is based upon 'hydraulic theory' where the unit is a system of hydraulic circuits.

The hydraulic fluid in the circuits is like electricity flowing in an electrical system, where things turn on or off by fluid pressure acting upon springs and valves in the 'valve body' -which is like the switchboard of the unit. (where fluid pressure is like electrical voltage, pushing through the wires etc)

Now the clutches and bands inside the automatic transmission are in analogy, similar to the brake system on our cars.

-the 'friction plates', acting upon the 'steels' (inside the front and rear clutches) is like 'disc brakes' on a car with 'hydraulic brakes'

-the 'bands' are like 'band brakes' on your go-kart when you were a little kid (but actuated with hydraulic fluid lines, not a metal actuation rod)

...so think of the frictions and bands like brake shoes; they have a 'friction lining' like the brake pads or brake shoes on your car.

Now drive your car 'dragging the brakes'... someone who does this will wear out their brakes faster.

More wear occurs when the brakes shoes are 'dragging' -making partial contact & 'slipping' the brakes instead of actually 'stopping the car'.

IF one applies more pressure to the brake pedal, the brakes won't slip but they will 'grab' and stop the car (hopefully!)

Same thing inside the transmission: more pressure and the frictions and bands 'grab' better instead of 'slipping' ...and/but when they slip a lot, they'll wear out sooner.

...Again, like the brakes on your car, if we stomp on the brake pedal, applying more pressure, it will make the car 'grab' to a 'harsh' stop. -as opposed to applying gentle foot pressure to bring the car to a 'comfortable' stop.

-the gentle pressure though, depending on how 'gentle'... will indeed greatly affect the lifespan of the brake shoes (try not to 'drag the brakes' in your car, or you'll be paying to install new brake shoes sooner than later)

Same thing, same analogy: If we apply more fluid pressure inside the auto trans, the frictions and bands will be more inclined to 'grab harshly' instead of a more 'gentle' shift 'feel'.

...Now the OEM designers of these automatic transmissions are always trying to eliminate the feel of 'hard shifts'... -the original goal was to make the car 'feel like it has a one speed transmission' -for that 'jet-thrust feel' -like a 'rocket car' or a 'jet car' (appealing to the higher technologies, for automotive higher tech charisma)

So the automatic transmissions on our vintage AMC cars were set up to provide a smooth shifting feel -to imitate 'jet thrust power'...

And this was the purpose of trying to use oversize/giant CID engines with two speed automatic transmissions; to create a 'jet like power' driving experience. (just stomp on the gas pedal and it 'takes off' in one seemingly smooth motion -like it has a jet engine in the car)

Nowadays, one may be aware they are still trying to do this in those cars with CVT; 'continously variable transmission' -where the car has no shift 'feeling' whatsoever.

So... this is part of the main purpose of installing a 'shift kit': to eliminate slip, which 'improves' the durability and generally makes the transmission feel more firm.

But another part of installing 'race shift kit' is to 'raise the shift point' to a higher rpm (when the transmission 'decides' to shift gears automatically)

On our vintage AMC Flash-O-Matic and Shift Command units, the max rpm shift point is around 4800 rpm.

-It's made that way to work with the powerband of the stock engine(s).

(where the stock engines are made to have an approximate 4000 rpm wide usable powerband; from about 800 to 4800 rpm)

But when an engine is modified, like 'putting in a cam', many times the cam allows the engine to 'rev higher', but the transmission then, will shift too early.

So the shift kit (depending on the kit) is also intended to 're-program' the shift points in order to work in harmony with the re-worked engine.

Judging by my personal two fastest cars I've ever built using this same basic unit (one with M11B, and one with 10B) -you just 'hold it in gear' and the upper rpm shift point is of no consequence, where the engine is able to rev up as high as you want it to -no problem.

XRV8 Gremlin (with M10B) is showing 'burnt fluid' though. It has 'paper' frictions.

The burnt fluid is from slippage during a gear change. (I should install new fluid)

I looked up that "Shift kit part number was 4488283" in the search window both ways and could not find anything.

http://theamcforum.com/forum/m12-performance_topic71054.html" rel="nofollow - http://theamcforum.com/forum/m12-performance_topic71054.html

Well done on maintenance and fluid changes!

Ok that's worn out for sure!

This is what I'm trying to describe by using the analogy of brakes on the car:

If one 'rides the brakes', this wears out the brake shoes.

-the band is just like a band brake (it is a band brake)

So this picture, as I understand it, tells me that band was slipping (excessive slip)

This would happen if the servo was binding, or if the seal in the servo was not sealing properly, then it couldn't apply with enough force for the band to grab (and not slip)

Those front servo seals are tricky to install. One needs 'three hands' to do it...

Thanks for not cussing me out for posting such long boring essays.

Alto's Catalog pages here:

I plan to try this idea when I'm able.

The FMX Red Eagle frictions and Kolene steels are on page 226 of Alto catalog.

These should swap into BW12, BW11B & BW10B.

Ok thanks for posting the links for me to read what's been said about 'shift kit for M12'.

Funny thing is, the quoted information says 'the valve body provides increased pressure'... (not word for word)

However, it can't. Only the pump can do that -just a minor technical issue...

I've done enough research to know for sure that by adjusting the throttle control cable on 10B, or vacuum modulator on 11B or 12, this does have a direct effect on line pressure to all circuits.

In other words -the adjustment raises or lowers the pressure from the pump to all circuits in the valve body. (this is somewhat stated in the quote but not exactly clear)

When the pump is making more pressure than needed, it has a dump valve that dumps excess pressure back into the pan (like if one were to shim the pump pressure spring with a penny etc) -This way, when the pump is making more pressure by means of the engine spinning faster, the pressure is regulated by the dump valve anyway so the valves, springs and plungers in the valve body still work the way they're supposed to regardless of what rpm the engine is turning.

(this was one of the minor changes Ford made to FMX; they changed the orientation of the dump valve slightly, on the pump)

Where 'plumbing' is an analogy for 'electricity', the dump valve is like the 'cut out switch' on an old school voltage regulator.

Sure, it's tricky to 'say it right' what-does-what.

In analogy, the throttle or modulator valve is like 'an adjustable doorway' from the pump, to the valvebody. (within the designed range of pressures; it only does so much)

Where plumbing is an analogy for electricity, the modulator valve is like the voltage regulator on the back of the instrument cluster.

Gary is in the far lane. 

https://youtu.be/r2wtBPYs3eE" rel="nofollow - https://youtu.be/r2wtBPYs3eE

my guy in stone Pk is a great builder 

Gary

Frank, I believe you are a good natured, kind hearted man.

 

The BW65 unit uses some BW35 internal parts, indicating it's evolutionary trace. This transmission offers no potential performance improvement for our vintage American Motors cars. It's more like a Ford C4, having it's band servos integral to the case (where one might say it looks like 'BW copied Ford a little bit') This transmission by the way, tends to de-elevate 'the Jaguar mystique' because IMO it is not robust or technologically superior in any way: it's just another light duty two band non-overdrive three speed automatic -without a cast iron case. Perhaps slightly more robust than Ford C4, I would rank this unit alongside early seventies GM TH250. It's all metric, like some versions of BW35.

 

The late-eighties Asin-Warner aka 'AW4' is a totally different all metric design. It's not an obvious evolution of the M8-12 series either. It is a 'thoroughly modern' electrically assisted unit that has no bands -all bands are replaced with large diameter disc type friction clutches instead, contrasted by ancient 1949 DG-200/250 design which is a three band two clutch unit.

 

A discussion of these units does serve the purpose of comparison, to help place the AM iron case units higher upon the scale of torque handling capacity; none of those units has the glorious heritage of having been used in a class winning supercharged alcohol Funny Car drag race category, where all those late-sixties AMC cars have 1000+ hp Grant Rebel SST for their super-hero role model.

 

 

"Ok, i know everyone is going to say just upgrade to the torqueflyte or turbo 400, but what really is wrong with the M12 as a mild/moderate performance trans?

 

I know parts for it are hard to come by, particularly any sort of performance upgrades but if you can get the Ford FMX to handle 500+ HP why can't the M12 do the same given their shared heritage? Surely for a mild performance street/strip engine, mine is closer to 350HP, the M12 or maybe even the M11 should be more than adequate and avoid the additional work and expense of swapping over to one of the other two."

-----------------------------------------------------------------------------------------

 

'Drop in' higher performance parts for our American Motors iron case automatics*:

 

Alto Red Eagle Frictions pn# 049740 or 049740UP5 (unit pack, 5 discs) front clutch, .060" thickness

Alto Red Eagle Frictions pn# 049742 or 049742UP5 (unit pack, 5 discs) rear clutch, .080" thickness

 

Alto Kolene Steels pn# 023701K or 023701KUP4 (unit pack, 4 plates) both clutches, .068" thickness

 

*should be 'drop in', but I have not done this myself. These are listed in Alto's online catalog, for Ford FMX on p.267 (current, as we speak) Notice in the catalog, the specifications are identical for BW8-12 frictions and steels listed on p. 526 (where the FMX traces it's evolution to BW8-12)

 

 

 

 

 

Where the more popular choices such as 727 or TH400 chop about 10 hp off power going to rear axle.

 

The difference is, as I see it, related to the diameter of the internal rotating parts, where the 727 and TH400 have larger diameter clutch drums and planetary units, the drain slightly more energy from the engine to make them spin.

 

In other words, the AM iron case units offer lower parasitic drag, for a performance benefit/increased power to the rear axle.

 

It does; the vacuum modulator is simply a different actuation mechanism than the throttle cable on some earlier models (like '65 M10B) Both do the same thing; they both manipulate a particular valve which is like 'a door' leading to all the other valves in the valve body, to raise or lower all pressure from the pump which is delivered to the valve body as a unit.

 

By adjusting the setting higher, it's like pressing on the brake pedal harder to make the brakes grab more firmly.

 

By adjusting the setting lower, it's like pressing on the brakes 'lighter' to make a 'gentle' stop, slipping the brakes instead (the more slip, the more 'smooth' the transmission 'feels')

 

Same thing with the brakes on a car: If the person tends to 'ride the brakes' (slipping the brakes while coasting etc) the brakes can overheat and the shoes will wear out much faster.

 

So when we see worn friction linings on the bands and friction discs inside the transmission, this tells us there was excessive slip happening in the unit.

 

Sometimes excessive slip can happen when a sealing ring, or an o-ring is somewhat defective, to allow a fluid leak in that particular hydraulic circuit.

 

Typical, when we see something like the fried band in Red's unit, this means basically all the 'soft parts' in the unit are damaged by excessive heat and should be replaced -all O-rings and shaft seals are most likely become 'hard' from overheating.

 

Don't let 'em run low on fluid. Don't overfill; this causes fluid aeration (not good for cooling or lubrication)

With the oil pump, as you say the volume of oil/pressure will be determine by engine speed. You will need a minimum pressure for the transmission to operate, let's say 60 psi, and you need a pump capable of generating that pressure at idle. The same pump might also then be capable of generating 500 psi at 6000 rpm, which would start to blow seals out of things perhaps. To overcome this, you have the dump valve as you mentioned, to bleed off pressure once you get to a certain point. My understanding is that this is the primary regulator valve, which is in the valve body? As I now realize, if you shim this spring or add a heavier spring, you will increase the maximum pressure available in the transmission at higher rpm.

Now the modulator further regulates the pressure based on either throttle position with a cable operated setup or engine vacuum with a vacuum modulator as in the case of the M11-12.

From the 71 TSM, which is presumably is the latest and most up to date version, it gives us some pressures to work with.

The vacuum pressure given should correspond to engine vacuum in drive at 1000 RPM with your foot on the brake.

One of the problems we might run into with a performance camshaft is the engine vacuum may be lower this. In a stock engine, if the vacuum is lower than specified, you fix the problem with the engine first.

This is sort of where I get hung up with lack of clear knowledge in this area as most people just say to fiddle with the modulator adjustment until you get the shift firmness you desire and maybe this is the best approach.

This is one of the most useful pieces of information in the TSM, because it shows what the oil passages do:

The TSM would have you believe that all pressures are measured at the one and only port in the case, when there are several ports and you need to use different ones to measure the different pressures in the table above. The TSM never makes that link.

One of the most obvious factory upgrades in these transmissions is the front band servo and this has been covered before. The M11B and M12 have a larger servo piston than the earlier M11 and also 2 bolts securing the servo rather than one. So they obviously identified that they needed more clamping pressure on the front band. In my case I started with a M11 of unknown condition and it ate the front band, I used a M11B case and mix of parts on the rebuild, assuming that the upgraded front band servo would solve the problem. I have had the two transmissions side by side and besides the front band and servo, the only other difference I could see was some very minor changes in the valve body, basically a couple of spring changes. Since I have has a similar, probably more sever failure with the rebuilt transmission it's possible I have other problems, or I have just abused it too much with foot on the brake burnouts shifting gears in the process as well as running it down the drag strip. Towards the end, I believe I may have also been having some problems with a sticky governor due to all of the crap in the oil from the damaged friction materials. I will certainly be paying more attention to checking the transmission pressures. For reference, I am probably sitting around the 350 HP mark.

The problem we have is that once the serious racers were able to use other transmissions for drag racing in the early 70's, all performance development on the BW transmissions ceased. 

This was to accomplish better band cooling, faster clamping and longer life.

The article did not specify what band material they used???

This is where we are stuck with the BW transmissions, nobody makes a shift kit, good, bad or indifferent. 

B&M worked with these transmissions 50 odd years ago, but any knowledge the developed, seems to have been lost.

Ford basically re-engineered the valve body with the FMX, so we are out of luck there unless we want so somehow adapt the FMX valve body. Even the FMX is starting to become a vintage piece exclusive to the resto crowd these days

I suspect it would be a good study for sake of comparison, but my gut feeling is: I bet it's cheaper/faster to manufacture the latter 'Simpson' style, to make more units in less time.

Concerning the Ford AOD unit and how that affects us as AMCers:

1) The AOD, with overdrive, is newer and more popular this drives demand up for higher performance parts.

2) Because the AOD is a mechanical evolution of the FMX, this means there are some interchangeable higher performance parts for our vintage AM WG units.

I'll post next, a group of pictures to help explain what is what.

That's a terrible feeling when a person gets flagged as a liar when they only made a silly mistake or said something that was 'a little bit off' for lack of showing more serious technical composure.

I know this, because prior to seven years ago I used to get drunk and mess around on AMC Forum just for fun, and sometimes said things that were technically incorrect. (only making a fool out of myself)

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Fortunately, I still have half a brain left... I think...

So... doing more research to learn about AOD part potential for swapping into FMX or AM iron case units, the prognosis is not all that great.

Because, as we will clearly see, the parts became cheapened, and became weaker as the AOD evolved into AODE and 4R70W.

In fact, Sonnax makes a whole new replacement 'solid' clutch drum to replace the cheap stamped steel 'flimsy' units in the newer versions of AOD.

Here's a link to the Sonnax video (AOD evolved into 4R70W):

https://www.youtube.com/watch?v=vNThS1MpfL8" rel="nofollow - https://www.youtube.com/watch?v=vNThS1MpfL8

Sorry out of order but for those people who would like to avoid the somewhat notorious 'reverse clunk' (which becomes more severe by 'turning up' pressure by adjusting vacuum modulator (M11B & M12) or throttle cable (M10B)...

Raybestos still offers a dished steel drive plates for the rear drum (aka 'third and reverse drum) -these soften the engagement into reverse and third gear:

Raybestos pn# 511035, replacing Ford pn#B1AZ-7B442-A, D3AZ-7B442-B

-The Ford dished plates are still common for sale on eBay -search for 'FMX', 'Cruise-O-Matic' and 'Ford-O-Matic'...

Along with using dished steels in the rear clutch, one may discover another reason why they sometimes used bronze lined 'radial pattern' frictions was to allow those frictions and steels in the rear clutch to spin freely during first gear engagement; the dished steels positively ensure the rear clutch frictions are not making full contact while the unit is in first gear -or the rear clutch is likely to 'drag' & create a little more heat even though it's not fully engaged by full hydraulic pressure. Long story short, the radial bronze lined frictions should be used in the rear clutch pack with dished steels to avoid 'reverse clunk' effect -if that is an issue frowned upon by the owner/operator of the vehicle.

Next problem is, I can't find 'radial pattern' bronze frictions (nowhere for sale anymore, as far as I know)

I think the Alto pn# is 049700BR ...for the 'radial' bronze friction that should go in the rear clutch with dished steels. The Alto pn# for Ford-O-Matic dished steels is 023703

I can only find 'forklift bronze frictions' sold by MinnPak, steeringclutch.com and/or highwayandheavyparts.com ...Case pn#181158A1 and/or Champion pn#28305

Note: Forklifts may spend much time moving heavy loads, always shifting between forward and reverse; since they use bronze frictions, that should tell us something about their durability... (eg: such as a forklift carrying several stacks, or 'lifts' of sheetrock, where only 'one lift' of sheetrock placed in a Super Duty Ford pickup truck makes it 'squat hard' -seriously)

Ok... I'll just go ahead and get this out of the way... since the AOD evolved from FMX (and Ford began to cut half as many teeth for the drive plate 'steels' on FMX around 1972... by doing half the work, they could double production capacity -to make two million units instead of one million?)

-pics showing how they cheapened the AOD clutch drums as time went by (if only for comparison):

Notice on this one, pictured above, the slots for the drive plates aka 'steels' are half as many: this is how the 1972-up FMX clutch drums are machined, having half as many splines, to double production by doing half the work making the part...

compared to later stamped steel type:

Because making the same part using stamped steel process, and since the steel is less robust and less wear resistant (because iron contains molecules of graphite for friction reduction), the newer AOD/4L60EW units 'feature' more spines again, but the later style engagement pattern for the 'steels' is not interchangeable with the earlier clutch drums (sure bet; it was made to metric dimensions)

This means we can't retro-fit the new style Alto Kolene coated steels made for this unit into the older FMX or AM iron case units (the newer HP AOD Kolene plates are made thinner to allow doubling the amount of friction plates in these later stamped steel clutch drums)

space for comment

When FMX got modded to have an overdrive and lock up torque converter, a new input shaft was designed for the neccessary fluid flow into the torque converter.

Seriously weakened, the AOD input shaft is not merely drilled for a passageway, it's hollow (thin wall):

...and we find 'Ford people' claiming this input shaft is good for 500 hp?

(the input shaft on FMX and AM iron case units is solid...)

There are companies who make billet steel (presumably hardenable alloy steel) input shaft and 'intermediate shaft' (aka 'primary sun gear shaft') for AOD, and the builders claim AOD can handle 1000 hp (!)    (like 1000+ hp '67 Grant Rebel SST using AM Warner Gear 11B)

...which, for some reason, seems like an unnatural coincedence, hearkening back to Rebel SST Funny Car?

...but they better be using a hardened billet steel input shaft since it needs to be hollow like that! (IMO)

When I worked on the E4OD transmission pod at Jasper Engines and Transmissions a few years back, we used a lot of Sonnax parts to upgrade our reman trannies so they'd meet or exceed the 3-year warranty. 

Cool Buzzman, thanks for your positive affirmation.

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Moreover, just for the sake of comparison, our AM Warner Gear automatic transmissions feature a one piece 'stator' hub. On Ford FMX units, they did less machine work to make the same part, which leaves the one piece stator drive hub even more robust ...having less iron trimmed off during the manufacturing process. -The FMX stator drive hub is slightly chunkier than the earlier Ford-O/Cruise-O and AM WG stator drive units.

However, GM's all-new-for-1965 TH400 'features' a two piece stator drive sleeve which is pressed into the front pump housing assembly... wow... that can't be good; there's bound to be problems with that they never tell about: The stator is a highly stressed arrangement of turbine blades held in a fixed position for the engine to redouble the force of fluid upon the input shaft side of the torque converter assembly.

Apparently, from GM TH350 through all the newer evolutions up to 4L80E continue the use of a two piece pressed in stator drive sleeve-to pump housing type construction. No doubt one may find hardened, 'one piece', billet steel replacements for these especially made for race duty.

Note: the GM 4L80E automatic transmission used behind many LS V8 engines is NOT a highly dependable transmission (!) It typically goes in for 'service' needing it's lock up torque converter rebuilt or replaced and needing the torque converter button reworked for becoming too sloppy; because the adapter on the back of LS V8 crankshafts/how it's made there at the crank flange: this gives the current transmission repair industry PLENTY of work fixing all those 'weak spots' on those vehicles. (!)

Read Sonnax article on this GM 4L80E aspect here:

https://www.sonnax.com/tech_resources/2-history-repeats-itself-worn-pilot-and-or-cracked-flex-plate-issues-return-on-the-gm-4l80-e-converters" rel="nofollow - https://www.sonnax.com/tech_resources/2-history-repeats-itself-worn-pilot-and-or-cracked-flex-plate-issues-return-on-the-gm-4l80-e-converters

Notice; we don't need it because our one piece stator assembly was made strong in the first place (IMO)

And notice; we don't need a hardened billet steel input shaft because our input shaft is solid, and more robust -similar thing again. (solid heat treated alloy steel on all FMX and AM WG units)

So, knowing this, it really 'eggs me on' to make a 'tit for tat' comparison:

Between an 'AOD built for 1000 hp' vs our vintage AM Warner Gear iron case automatic transmission

(for which we have 1000+ hp '67 Grant Rebel SST AMWG M11B unit for a role model 'race unit')

I'll try to make this tit-for-tat comparison next.

Per given weight to torque carrying ability, a hollow shaft is always better. The diameter is the critical factor in torque loads.

The wall thickness has to be large enough to handle the structural load of the splines in this case.

Just look at how thin they can make a driveshaft! 

Has anything ever been documented  on this 1000 horse capable M11?

Was it a fully functional  3 forward gears trans or did it only have a torque converter, front pump and an output shaft passing through it.

 Add gun drilled race axles to the list.  For over 10 years at least 2 of the automakers have been using tubular sway bars. Stronger and lighter than a solid bar.

I tried, when trying to troubleshoot slipping 2nd gear i replaced worn out rigid M12 band with FMX flex band. One needs to adjust the height of the anchor pin with washers so that auto adjuster will be in correct position on the other end. I had to trim the trans housing in area around the anchor pin a bit (flex band anchor end is slightly larger). Sadly the band did not help and i have had no time to troubleshoot it more, 2nd gear still slips.

and locked stud in place, like I think AMC did on the M12 ? and / M11B ?