2.87s to 3.15s, need help, with set up?

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   bought a used 3.15 set on hear a year ago or so and time to install
is now. 
I'm no expert by far, but ive done 15-20 in my life time, with decent results
each time.     this one is giving me a fit . no  markings on gear set.
with everything the same as removed(I used the bearing off the stock pinion) I had .026  when checking the ring movement with a dial
indicator. so I moved the ring closer to the pinion , got it about .010 and had a ratcheting
noise when turning the yoke by hand(slight noise before moving the ring). I think the pinion needs to go deeper , which would allow 
the ring to be back in stock(ish) position. the pattern on the pinion is all the way down at the bottom
of the pinion. and I can t get a good reading on the ring , looks to be toward the inside maybe.
anyone know where to start with lowering the pinion, ive took it out and can answer any 
questions.
HELP Before I go nuts!
car is 72 mat,401,727 with untouched rear until now, 60,000 mile car when I got.
drove it for years with the 2.87s and wanted a little more bottom end(really like the 3.15s in my
70 4- door rebel with a 455 indian under the hood.
thanks.
all ideas welcome !

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amc401t10 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903	Post Options Post Reply Quote amc401t10 Report Post Thanks(0) Quote Reply Topic: 2.87s to 3.15s, need help, with set up? Posted: Apr/27/2017 at 5:23pm
	bought a used 3.15 set on hear a year ago or so and time to install is now. I'm no expert by far, but ive done 15-20 in my life time, with decent results each time. this one is giving me a fit . no markings on gear set. with everything the same as removed(I used the bearing off the stock pinion) I had .026 when checking the ring movement with a dial indicator. so I moved the ring closer to the pinion , got it about .010 and had a ratcheting noise when turning the yoke by hand(slight noise before moving the ring). I think the pinion needs to go deeper , which would allow the ring to be back in stock(ish) position. the pattern on the pinion is all the way down at the bottom of the pinion. and I can t get a good reading on the ring , looks to be toward the inside maybe. anyone know where to start with lowering the pinion, ive took it out and can answer any questions. HELP Before I go nuts! car is 72 mat,401,727 with untouched rear until now, 60,000 mile car when I got. drove it for years with the 2.87s and wanted a little more bottom end(really like the 3.15s in my 70 4- door rebel with a 455 indian under the hood. thanks. all ideas welcome !
	1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int. 72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2

Lyle Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jul/17/2014 Location: None Status: Offline Points: 772	Post Options Post Reply Quote Lyle Report Post Thanks(0) Quote Reply Posted: Apr/27/2017 at 7:21pm
	That "ratcheting" noise is likely noise from a wear edge on the gear teeth or the pinon/ring gears bottoming out which would also have binding. I'm assuming new bearings and you haven't stated track lock ... With what you have stated try and rotate the ring gear 90° and then 180° to see if is a wear problem from an original poorly aligned housing or gears. If you can setup - to spec - without the "ratcheting" doing this then go for it! Failing this I believe you need a new gear set.

purple72Gremlin Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Charter Member Joined: Jul/01/2007 Location: Illinois Status: Offline Points: 16611	Post Options Post Reply Quote purple72Gremlin Report Post Thanks(0) Quote Reply Posted: Apr/27/2017 at 9:25pm
	Used gears really are not easily set up as they have worn together, and if you didnt know what they were set at, well, they will be noisy and not last IMHO.......

1970390amx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3314	Post Options Post Reply Quote 1970390amx Report Post Thanks(0) Quote Reply Posted: Apr/27/2017 at 10:50pm
	How thick is the depth shim located under the rear pinion bearing race in the housing?
	1970 390 4speed Bittersweet shadow mask AMX 1970 Amx missing most everything, or in a box

tufcj Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Supporter of TheAMCForum Joined: Jul/10/2007 Location: Watkins, CO Status: Offline Points: 4086	Post Options Post Reply Quote tufcj Report Post Thanks(0) Quote Reply Posted: Apr/28/2017 at 8:59am
	Probably needs additional shims under the pinion. A pinion depth tool is a great investment if you do a few setups. All the AMC20 axles I've set up require .100+" of shim under the pinion. AMC had .085+" thick single shims available from the factory. Like said above, used gears are harder to set up than new gears since they have an established wear pattern. It's usually hard to get that pattern back without measuring before they're removed. I also NEVER set up with used bearings, as clearances WILL change once new bearings are installed. For axles that I do regularly, I bought an extra set of bearings and clearanced them so they're a tight slip fit. I use those for setup, then press on the permanent bearings once everything is set. Bob tufcj
	69 AMX 74 Javelin AMX 67 Rogue If you need a tool and don't buy it... you'll eventually pay for it... and not have it. Henry Ford

amc401t10 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903	Post Options Post Reply Quote amc401t10 Report Post Thanks(0) Quote Reply Posted: Apr/28/2017 at 9:27am
	095 Think the pinion needs more shim, it dissent look like it is meshing all way down to inside of ring gear.I've got .140 stack to go in and try.
	1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int. 72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2

1970390amx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3314	Post Options Post Reply Quote 1970390amx Report Post Thanks(0) Quote Reply Posted: Apr/29/2017 at 1:12am
	I would only go .005-.006 at a time.
	1970 390 4speed Bittersweet shadow mask AMX 1970 Amx missing most everything, or in a box

amc401t10 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Mar/09/2009 Location: east tn Status: Offline Points: 903	Post Options Post Reply Quote amc401t10 Report Post Thanks(0) Quote Reply Posted: Apr/29/2017 at 10:02am
	I'm adding .060 today and will post results
	1-owner 74 gremlin x 401, t10,3.73 12 bolt,750carb,reed 250@50 cam, roller rockers,msd,offy int. 72 amc matador 401 727 84 j10 ,360, 727 1970 4-door rebel sleeper(455 pontiac,turbo 400) 79 spirit,4.2

1970390amx Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jul/11/2008 Location: colorado Status: Offline Points: 3314	Post Options Post Reply Quote 1970390amx Report Post Thanks(0) Quote Reply Posted: Apr/29/2017 at 1:01pm
	I think all the model 20 diffs I have worked on have shims around .100 give or take a few. A .060 change is huge and I bet you still have major setup problems
	1970 390 4speed Bittersweet shadow mask AMX 1970 Amx missing most everything, or in a box

401jim Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/07/2012 Location: Brunswick,Ohio Status: Offline Points: 793	Post Options Post Reply Quote 401jim Report Post Thanks(0) Quote Reply Posted: Apr/29/2017 at 1:24pm
	If you have a 287 carrier it will not take a 315 ring and pinion. You need a 3 up carrier to work. Hope this helps you. Jim