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Twin Grip Rebuild

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danleym View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote danleym Quote  Post ReplyReply Direct Link To This Post Topic: Twin Grip Rebuild
    Posted: Dec/05/2021 at 6:36pm
Anyone have any good info on rebuilding a twin grip? I can handle the gearset and read end bearings easily enough, I'm more concerned about the differential itself- I have a Rear end of unknown provenance that has been sitting outside for a while, so I'm assuming I need to go through the diff. I've done some searching and haven't found much detailed info. 

Thanks!
Hollis Danley
1980 Spirit, 258
2000 VW Jetta TDI
2002 Jeep Wrangler, 4.0
2015 Subaru XV Crosstrek
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1970390amx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Dec/05/2021 at 7:57pm
what type?  year?

1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box
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Trader View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Dec/06/2021 at 6:12am
Some info on a 68 unit to make comparisons to what you have obtained:
Only thing I would mention beyond the friction modifier is to let the clutches sit in oil for 24 hours before assembly. Installing them dry can cause each side to lock up back and forth under heavy acceleration. Easy to loose control of the car swinging it's derriere like that at speed.
All clutch units of any make should be assembled this way for this reason. TSM's mention it but do not emphasize the importance of this.

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mbwicz View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mbwicz Quote  Post ReplyReply Direct Link To This Post Posted: Dec/06/2021 at 7:01am
If the axle didn't get water in it, you may be ok just checking backlash and looking for problems.  I would try and figure out what year it is from and get info from a TSM on what the specs are for inspecting and rebuilding.  Just a thought.

Mike

1970 AMX, one step forward, one step back. Both steps cost time and money.
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danleym View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote danleym Quote  Post ReplyReply Direct Link To This Post Posted: Dec/06/2021 at 7:10pm
It's a model 20 out of a Spirit. Not sure the exact year, but I doubt there was much difference between them.

The housing stayed sealed, with oil in it, and no water. I just don't know how long it sat, how many miles are on it, or anything else about it. I need to regear it, and I think I'd rather just go through it while I have it open, instead of getting the car all back together only to find out I need to go through it still.
Hollis Danley
1980 Spirit, 258
2000 VW Jetta TDI
2002 Jeep Wrangler, 4.0
2015 Subaru XV Crosstrek
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1970390amx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1970390amx Quote  Post ReplyReply Direct Link To This Post Posted: Dec/07/2021 at 1:16am
where in colorado do you live?
1970 390 4speed Bittersweet shadow mask AMX
1970 Amx missing most everything, or in a box
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Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Dec/07/2021 at 4:05am
Originally posted by danleym danleym wrote:

It's a model 20 out of a Spirit. Not sure the exact year, but I doubt there was much difference between them.

The housing stayed sealed, with oil in it, and no water. I just don't know how long it sat, how many miles are on it, or anything else about it. I need to regear it, and I think I'd rather just go through it while I have it open, instead of getting the car all back together only to find out I need to go through it still.
If it is indeed a model 20 out of a spirit, its a 1979. As that is the only year for a spirit to have a V8. And TG means 2.87 gears too
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Post Options Post Options   Thanks (0) Thanks(0)   Quote First_Gear Quote  Post ReplyReply Direct Link To This Post Posted: Dec/07/2021 at 11:36am
I just rebuilt a model 20. Mine was an open diff though no clutch pack. Better just take everything apart clean and inspect. Check tolerances per tsm. Inspect bearing races and rollers. If damaged then replace. If in good condition why fix what ain't broke. In my case axles were bent. Carrier bearings looked like the surface of the moon. All fixed.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve_P Quote  Post ReplyReply Direct Link To This Post Posted: Dec/07/2021 at 12:23pm
everything you need to know is in the TSM.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mbwicz Quote  Post ReplyReply Direct Link To This Post Posted: Dec/07/2021 at 12:35pm
In another post, it was recommended to source parts from Ratechmfg.com .  Apparently some places use 'similar' shims that may not be the ideal diameter for the AMC 20 axle.  I purchased parts from these guys and had no problems rebuilding my axle earlier this year.  

Mike
1970 AMX, one step forward, one step back. Both steps cost time and money.
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