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New TKX vs Old TKO

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troutwilly View Drop Down
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    Posted: Jul/05/2022 at 11:50pm
As some might have gathered from some of my posts, I've been doing quite a few mods to my AMX over the last 4 years. And I've promised a "project" post and still want to do that, but I just had to tell you about this TKX install.  It wasn't in the original plan.

I had a TKO600, installed back in 2010, had about 10K miles on it. I just recently added the hydraulic throw out bearing along with the whole CF suspension (which changes your drive line angles). I was getting some serious vibrations but wrote it off to bad wheels as I'd been told a couple were bent, but I found the drive line angles to be way off.  Also, I may have damaged the TKO on reinstall as there was a "thud" when it slipped into place.  I drove it for a few months, until the TKO started having trouble going into 2nd and also seemed to have a lot of slop in it.  Did the "thud" damage it or was it vibrated to death, I don't know.

I wanted to have the TKO repaired but the only shop I could find near me wanted a $1500 drop off deposit.  Well that's half the cost of a new TKX, so here I am.

The install was super easy and the TKX is much smaller (diameter) than the TKO.  I know the TKO was probably hitting my tunnel, but I can get my hand above the TKX.  It was an exact replacement, just better fitting.

But the reason I write this is because I just finally drove the car up and down my street and I'm grinning, ear to ear, cause this TKX shifts way better than the TKO, even when the TKO was new.  Its a stiffer shift but way more positive.  A strong spring moves it to the 3-4 location so you need to hold it over when going to 2nd.  Big smile = cost justification.

The TKO was a 2.87 first and 0.64 fifth.
The TKX has the 2.87 first with the 0.68 fifth. 

I'll get it out on the road as soon as I can to see how it feels at speed and to see if I correctly corrected the drive line angles (involved a 1/4" shim under the transmission mount and adjusting the links on the rear end.  If the vibration is gone, I'll be one happy camper.
Bill O.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 390amx1 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/06/2022 at 5:29am
Subscribed.  Willy, I have a similar situation.  With the TKO in the AMX and up as close as I dare to the tunnel (don't want to modify that) I have the engine downward 4.5 degrees.  The drive shaft is downward at 1+ degrees.  To compensate a little I put shims in the rear for 2 degrees up.  The difference now being 3.5 degrees which is on the edge of too much.  I do have ever so slight vibration around 60-75 mph that I'm certain is due to driveshaft angle.  Please report back if you think the TKX switch out helped...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote troutwilly Quote  Post ReplyReply Direct Link To This Post Posted: Jul/07/2022 at 12:56am
Plugging your numbers into the Spicer calculator shows 3.5* on the front universal and 3.0* on the rear universal.  I would say that at 3.0* you're pushing the limit and at 3.5* you're over.

When I did the TKO install I realized the transmission would be way too close to the tunnel, so I modified mine a little, about 1/4 inch, but I'm no metal worker and think I was only marginally successful.  I had about a 1/8" shim under the trans mount, I believe the transmission would hit the tunnel, but I wasn't experiencing any radical vibrations.  Its been so long I don't remember any angles or calculations.

Fast forward several years and I installed the CF font and rear suspensions.  I believe the TKO still hit the tunnel.  The rear suspension is totally different though.  Originally the guys who set it up had the axle at 5* pinion down (which is up on the calculator).  The transmission was similar to yours at 4.4* down with the driveshaft at 1.8* down.  So I had 2.6* at the front universal and 6.8* at the rear universal.  I didn't verify their work and was driving it that way.  Finally got to checking it and holy bat poop.

So now, with a TKX, a little more experience, a digital angle finder, about a 1/2" spacer under the trans mount, adjusting the links on the rear end, and a lot of trial and error, I have:
3.4* down on the transmission (a 1* difference),
1.0* down on the drive shaft, and
1.3* up on the pinion (took out at least 3.7*), I now have
2.4* on the front joint and 2.3* on the rear joint.

Took it out on the highway and I love it.  Very little vibration which I believe could be due to bent wheels and the CF design.

I don't think you'll be able to space the TKO that much without tunnel mods.  But put a jack on it and lift it until it hits the tunnel and back off a bit.  And remember, when you change the trans angle or the pinion angle, you also change the drive shaft angle.  so measure it all after every change.  Playing around with the calculator and assuming some drive shaft change with every trans/pinion change, if you can get the trans to 4.2* down, the pinion to 1* up, the driveshaft might be at 1.3* down which would give you 2.9* and 2.3* on the universals.

Will the TKX help all this fall into place, I'd say yes.  I could probably still shim it higher.  But its the expensive way to go.


Edited by troutwilly - Jul/07/2022 at 12:58am
Bill O.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 390amx1 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/07/2022 at 6:12am
Interesting.  I would have thought with the TKX you could really put it up much closer to the tunnel to get maybe 2 degrees down (or even less if you wanted) on the trans.  If I spend the money to change from a TKO to a TKX and only gain about 3/4-1 degree angle that's not enough to me for the investment.  As far as my TKO goes, I think its already up as high as it can go as I did jack it up to where it was just rubbing and took off a smidge to install the trans crossmember.  IIRC I have it a 3/16 inch shim up from the Silver Sport trans mount that came with it.

Edited by 390amx1 - Jul/07/2022 at 6:16am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote troutwilly Quote  Post ReplyReply Direct Link To This Post Posted: Jul/08/2022 at 9:44pm
I only shimmed it up as far as I needed.  It can go farther but I don't know how much.  As it is now I can run my hand over the top edges on both sides so would guess maybe another half inch.
Bill O.
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