80q rear diff

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DE80q
Posts: 2572
Joined: Mon Mar 04, 2013 9:25 am
Location: York PA 17403

80q rear diff

Post by DE80q »

As of late, the on/off throtle in my 80q has become quite violent. I remember thinking the rear diff seemed to have a little more slop than I thought it should. I have another rear diff from my parts car, but it has more mileage than my current unit. Now having said that, that is with an NG, so I would imagine it didn't see quite the abuse that the current one has, or that others have thrown on to theirs.

The question is, has anyone ever rebuilt one of these? If you have, can you share any specs you may have for them? I'm sure others have done this, I can be the first who wants to do it.

Thanks for any advise.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
Afterthought
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Joined: Thu Jan 16, 2014 5:43 pm
Location: Bellingham, Wa

Re: 80q rear diff

Post by Afterthought »

You’re thinking It’s the differential itself ? Not the mounts?
DE80q
Posts: 2572
Joined: Mon Mar 04, 2013 9:25 am
Location: York PA 17403

Re: 80q rear diff

Post by DE80q »

Afterthought wrote:You’re thinking It’s the differential itself ? Not the mounts?
The mounts have all been replaced with Jarid's "epic mounts". I'll have to check them out as well, they should be fine though.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
Lucky
Posts: 104
Joined: Sun Jul 19, 2015 11:16 am

Re: 80q rear diff

Post by Lucky »

Is there any play in the driveshaft and CV joints?
1988 Audi 80 quattro, 2005 Ranger, 2006 BMW 330i, 1996 Yamaha Virago
DE80q
Posts: 2572
Joined: Mon Mar 04, 2013 9:25 am
Location: York PA 17403

Re: 80q rear diff

Post by DE80q »

Lucky wrote:Is there any play in the driveshaft and CV joints?
The drive shaft was replaced with a better one, and the CV's were all checked. Everything seemed tight, except when checking the the amount of play in the diff.
"If you can't find one, make one"

Dallastown, PA
1991 Audi 80 quattro (20vt project)
1991 Audi Coupe Quattro (project: my first 20v)
2007 Mitsubishi Raider(Dakota in disguise)
2019 Chevy Cruze RS hatch (wife's little red sporty car)
ChrisAudi80
Posts: 875
Joined: Sat Mar 02, 2013 11:37 pm
Location: Bangkok, Thailand

Re: 80q rear diff

Post by ChrisAudi80 »

I have slop in my C4 diff, so it's not unthinkable. They do wear after a while. Mine only has 200k kms on it, but I recently found out it is leaking a little.
96 S6 auto
95 80Q AEB VEMS
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themagellan
Posts: 873
Joined: Tue Mar 05, 2013 10:36 am

Re: 80q rear diff

Post by themagellan »

Check your driveshaft support.

even if the trans mounts are new make sure you installed them correctly. May even be worth check the engine mounts.

If you can get it up in the air you can put some pressure in areas to see if there is any flex. I would be surprised the violent on/off Accel would be internal to the diff.

One other idea - You can also cram styrofoam where the trans mounts are to see if you're getting any unneeded compression. If they are unscathed after a quick ride you can probably check the mounts off the list.
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