Print Page | Close Window

70 AMX rear axle ring/pinion brand question

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: Transmission & Drivetrain
Forum Description: If it's between the engine and wheels, it goes here
URL: http://theamcforum.com/forum/forum_posts.asp?TID=100852
Printed Date: Nov/21/2019 at 8:38am


Topic: 70 AMX rear axle ring/pinion brand question
Posted By: bvpotash1
Subject: 70 AMX rear axle ring/pinion brand question
Date Posted: Jul/04/2019 at 9:21pm
Many years ago I bought a motive gear 3.73 ring and pinion for my 70. I'm just getting around to installing it. Has any one had a experience with this brand? It is made in Italy. Also I misplaced the pinion shim that goes behind the large bearing race. Any ideas what shim I should star with when setting up this new gear set? I also need new posi clutch plates. I bought the ones with the round corners, later model? I have the carrier that bolts together with square corner plates. As always thanks for your help, it is greatly appreciated.

-Bernie  



Replies:
Posted By: NCSteve
Date Posted: Jul/10/2019 at 7:10pm
I just installed 4.88 motive gears in my JKU Rubicon. Lots of folks in my area use them with no issues. I always start with what was originally the housing and normally is really close starting point. 

-------------
1970 Big Bad orange AMX, 390 4speed, Go Pac
1979 Jeep Cherokee, 360, 4 speed/D20
2015 JKU Rubicon Tank Green


Posted By: 401MATCOUPE
Date Posted: Jul/10/2019 at 7:28pm
You may have issues with Motive or any brand for an AMC 20, they are not machined to use thefactory tools and I have little luck with them, actually sources a used set and returned all new ones.  Pit Crew AND i have had same experience.....good luck. 

-------------
Ross K. Peterson
68X,GoPac,343,AT,52A(1stCar)
68X,GoPac,390,4sp,52A
69X,GoPac,390,4sp,64A
70X,GoPac,390,4sp,87A,8
70X,GoPac,390,4sp,BBO,8
70 Jav SST,390,AT,BSO
74MatX,401,AT,Prototype
74MatX,401,AT


Posted By: tufcj
Date Posted: Jul/10/2019 at 9:45pm
Since you don't have the original pinion shim, setup will be a little more difficult.  I'd start with a pinion shim of around .085-.095".  Pretty thick, the factory shim was cast iron.  The Yukon 3.73s in my AMX ended up taking about .102" to get a good pattern.

I recommend getting a shim kit from Ratech.  They have enough shims in their kit to build a pack that thick.  Most master kits use GM size shims which don't quite fit the AMC needs.

Bob
tufcj


-------------
69 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


Posted By: 1970390amx
Date Posted: Jul/10/2019 at 10:12pm
several sets of gears I set up ended up with a pinion shim in the area of .100 Do you want to sell the wrong set of posi clutches you have?

-------------
1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box


Posted By: WesternRed
Date Posted: Jul/11/2019 at 5:59pm
Get the solid pinion spacer from Ratech as well, should make it easier to swap in and out without having to worry about the crush tube.

-------------
I've finally given up drinking for good...........now I only drink for evil.


Posted By: pit crew
Date Posted: Jul/12/2019 at 7:25am
Originally posted by 401MATCOUPE 401MATCOUPE wrote:

You may have issues with Motive or any brand for an AMC 20, they are not machined to use the factory tools and I have little luck with them, actually sources a used set and returned all new ones.  Pit Crew AND i have had same experience.....good luck. 
Yes, we went through every brand of new gears you can think of and they all had the same problem. The pinions are all made in Italy now. They are too long and have a square shoulder that will not let the pinion nut lock all the way down.

Of course calling all of the "manufactures" tech support produced the same answer. "Never hear of that before.". This was in spite of the fact I had talked to other AMC people that said they had already called in the issue themselves.





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

73 Hornet - 401EFI - THM400 - Twin Grip 20


Posted By: Steve_P
Date Posted: Jul/12/2019 at 8:59am
I haven't done any in a while, but .08-.10" sounds like what I've seen with OE gears. I use the TSM method and measure off the back of the pinion gear like Ross.


Posted By: bvpotash1
Date Posted: Jul/12/2019 at 11:37am
I'd like to thank every one for the fantastic information and incite! This Form and its members are truly the best!

THANK YOU!
-Bernie


Posted By: PHAT69AMX
Date Posted: Jul/12/2019 at 3:46pm
Did someone already mention using some "old" pinion bearings and honing the id so they are slip fit and use those to get a set up shim size, then do final assy with new pressed on bearings only 1 time, hopefully?

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


Link to a http://www.youtube.com/watch?v=MySiKQsmWxU" rel="nofollow - Short YouTube Burnout Video



Posted By: Steve_P
Date Posted: Jul/31/2019 at 7:08am
I ran across my notes on this and I've seen a range of .093-.110. Which coincidentally is the shim range that AMC produced.
If you use the factory method and measure off the back of the pinion there is no assembly/disassembly trial and error.



Print Page | Close Window