Need rear end advice
Thread Starter
Teching In
Joined: Mar 2014
Posts: 3
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Need rear end advice Hello all,
Need some advice on what to do. Car is a 2000 TA A4 with 4 channel rear. 105k.
Apologies up front as this post is a little windy but I figured it is best to post where I am coming from.
Detailed log of events:
While ago the pinion seal started to leak. Had it replaced at shop near where I live. Then I had a technical issue that I decided it better go to a GM dealer to get fixed (wouldn't start/turn over and I knew it was not the starter, ign switch, or relay. Turned out to be aftermarket anti theft sys failure). There they noted pinion seal was still leaking. So I went back to first shop thinking they just didn't do it (also had tranny tailshaft seal fixed when it first was there too) and the shop replaced pinion seal for free. Took a Saturday cruise last weekend and started to hear noise. I was 130mi from home and I had to be back by a certain time so my hand was forced to drive on. By the time I got home 3 different noises could be heard, that got progressively louder (thinking wheel and carrier bearings) and a very noticeable axle grease smell inside my garage after parking. No vibrations or clunking noise. After reading various threads here I am assuming an improper fix was done and my rear ran itself out of oil on the road trip. I have not touched the car since getting it home.
Now, my situation. I bought the car a year ago to have as a weekend cruiser. Very clean car, very well taken car of, one owner, still had factory plastic on floor boards, all stock, no signs of teenager abuse. But it had sat for a couple of years prior and I have run into issues because of that. I am tired of spending money on it. With the exception of the magnaflow I put on it is going to remain all OEM. I do not have the proper tools or room to perform repairs myself. So my questions are:
As far as I drove it with noise, would anyone here try to rebuild the rear or look for one in a salvage yard? I am thinking cost control from having a shop do repair or replace
I am thinking the pinion and gear are probably damaged, what about the axles? If the rear was pulled apart, chances axles would have to be replaced?
If I found rear in a salvage yard that did not have trac control or ABS (was abs standard on 4th gens?) could I use prexisting parts off current rear to make it work? I dont actually care about ABS or trac control, I just don't want to stare at dash lights.
My car has a GU2 axle. I really do not have a preference on what ratio goes back in it except, how hard would it be to calibrate a GU6 or GU4* axle as GM as the v8 A4 never left the factory with that? (I am clueless what a dealer could do and I am not interested in buying a device just for speedometer calibration. But to keep the mileage right, I do want it calibrated).
*if I found a GU4 with posi out of a v6 car (I do not want a "one tire fire" -read that on here, love it) would it hold up ok? I think all the internals are the same but I want to be sure.
Lastly, what should I look for on a salvage rear to ensure I do not run into more issues?
I appreciate any help. I am just a bit frustrated right now with it being one thing right after another with this car after I thought it was a good one.
Need some advice on what to do. Car is a 2000 TA A4 with 4 channel rear. 105k.
Apologies up front as this post is a little windy but I figured it is best to post where I am coming from.
Detailed log of events:
While ago the pinion seal started to leak. Had it replaced at shop near where I live. Then I had a technical issue that I decided it better go to a GM dealer to get fixed (wouldn't start/turn over and I knew it was not the starter, ign switch, or relay. Turned out to be aftermarket anti theft sys failure). There they noted pinion seal was still leaking. So I went back to first shop thinking they just didn't do it (also had tranny tailshaft seal fixed when it first was there too) and the shop replaced pinion seal for free. Took a Saturday cruise last weekend and started to hear noise. I was 130mi from home and I had to be back by a certain time so my hand was forced to drive on. By the time I got home 3 different noises could be heard, that got progressively louder (thinking wheel and carrier bearings) and a very noticeable axle grease smell inside my garage after parking. No vibrations or clunking noise. After reading various threads here I am assuming an improper fix was done and my rear ran itself out of oil on the road trip. I have not touched the car since getting it home.
Now, my situation. I bought the car a year ago to have as a weekend cruiser. Very clean car, very well taken car of, one owner, still had factory plastic on floor boards, all stock, no signs of teenager abuse. But it had sat for a couple of years prior and I have run into issues because of that. I am tired of spending money on it. With the exception of the magnaflow I put on it is going to remain all OEM. I do not have the proper tools or room to perform repairs myself. So my questions are:
As far as I drove it with noise, would anyone here try to rebuild the rear or look for one in a salvage yard? I am thinking cost control from having a shop do repair or replace
I am thinking the pinion and gear are probably damaged, what about the axles? If the rear was pulled apart, chances axles would have to be replaced?
If I found rear in a salvage yard that did not have trac control or ABS (was abs standard on 4th gens?) could I use prexisting parts off current rear to make it work? I dont actually care about ABS or trac control, I just don't want to stare at dash lights.
My car has a GU2 axle. I really do not have a preference on what ratio goes back in it except, how hard would it be to calibrate a GU6 or GU4* axle as GM as the v8 A4 never left the factory with that? (I am clueless what a dealer could do and I am not interested in buying a device just for speedometer calibration. But to keep the mileage right, I do want it calibrated).
*if I found a GU4 with posi out of a v6 car (I do not want a "one tire fire" -read that on here, love it) would it hold up ok? I think all the internals are the same but I want to be sure.
Lastly, what should I look for on a salvage rear to ensure I do not run into more issues?
I appreciate any help. I am just a bit frustrated right now with it being one thing right after another with this car after I thought it was a good one.
For what you are doing I would do one of two things... replace the entire rear with a known good one, or spend a few more bucks and have a reputable shop rebuild what you have.
You can typically get a good used 10 bolt for 250-500 but if you have to ship it that can add another 250 real easy. I can set you up with all new internals(Posi, gears, bearings, install kit, etc) for around 800.00 using all high quality parts like a genuine Eaton clutch posi unit.
All 4th gen cars have abs(3ch), not all had traction control(4ch) though. Traction control can be identified by if you have a button on the dash or console to turn off the "ASR" or 'TCS". 3ch and 4ch rearends can swap parts, but the cost may not be worthy in the end.
Typically the auto trans cars had a 3.23 gear, the M6 cars had a 3.42.
You can typically get a good used 10 bolt for 250-500 but if you have to ship it that can add another 250 real easy. I can set you up with all new internals(Posi, gears, bearings, install kit, etc) for around 800.00 using all high quality parts like a genuine Eaton clutch posi unit.
All 4th gen cars have abs(3ch), not all had traction control(4ch) though. Traction control can be identified by if you have a button on the dash or console to turn off the "ASR" or 'TCS". 3ch and 4ch rearends can swap parts, but the cost may not be worthy in the end.
Typically the auto trans cars had a 3.23 gear, the M6 cars had a 3.42.
IMO it sounds like the shop that did the rear end work is responsible for the issue, I would call them up and tell them that this happened when driving home and you have not driven since... At least that's what I would do.
As far as a 3 channel working on a 4 channel car I don't think there is any way you can hook that up and you will have ABS and TCS lights on your dash not to mention your ABS block will be freaking out and won't work right. Also getting it calibrated is easy if you have HP tuner software or know someone who does, its as simple as just changing the axle ratio, not sure if they would need an extra license for it though so the price might be up to $150 or so depending on if it requires the extra license.
As far as a 3 channel working on a 4 channel car I don't think there is any way you can hook that up and you will have ABS and TCS lights on your dash not to mention your ABS block will be freaking out and won't work right. Also getting it calibrated is easy if you have HP tuner software or know someone who does, its as simple as just changing the axle ratio, not sure if they would need an extra license for it though so the price might be up to $150 or so depending on if it requires the extra license.
GU2=2.73 base V8 posi rear for automatics
GU4=3.08 A V6 rear without Posi
GU5=3.23 optional performance rear axle for V8 automatics
GU6=3.42 V8 posi rear for manuals
up to and including 1998 had Auburn 'posi
1999 and later had Torsen 'posi'
3 channel is ABS only with the sensor on top center of rearend
4 channel is ABS & TC with a sensor at each of the rears' brake backing plates
A 3 channel rear can be converted to 4 channel by using/installing the 4 channel axles and backing plates into/on the 3 channel rear.
In the 1998-2002,all the internals are 'interchangeable' except for gearsets in the fact that you can't use a pinion gear without another ring gear for which it was not made for and carrier bearing caps cannot be mixed.
Since you're GU2/2.73,a GU5/3.23 or GU6/3.42 will require a computer change to get the mph and odometer correct
GU4=3.08 A V6 rear without Posi
GU5=3.23 optional performance rear axle for V8 automatics
GU6=3.42 V8 posi rear for manuals
up to and including 1998 had Auburn 'posi
1999 and later had Torsen 'posi'
3 channel is ABS only with the sensor on top center of rearend
4 channel is ABS & TC with a sensor at each of the rears' brake backing plates
A 3 channel rear can be converted to 4 channel by using/installing the 4 channel axles and backing plates into/on the 3 channel rear.
In the 1998-2002,all the internals are 'interchangeable' except for gearsets in the fact that you can't use a pinion gear without another ring gear for which it was not made for and carrier bearing caps cannot be mixed.
Since you're GU2/2.73,a GU5/3.23 or GU6/3.42 will require a computer change to get the mph and odometer correct
Thread Starter
Teching In
Joined: Mar 2014
Posts: 3
Likes: 0
Appreciate the tips. For some reason I thought the v6 came with a posi after the 3800 was introduced in 96? Oh well, does not matter as I have limited my search for used rear ends from cars with v8s. Also waiting on what the shop will offer me but they are not touching it again!
what's your location?
getting a rear axle with an open differential... the one tire fire... don't be so quick to knock it. if you only want the car to cruise and drive normally, on pavement, 95% or more of the time you won't notice the difference. open diffs are more simple, less weight, rarely fail.
you need to shop around for repair shops that are competent in rear axle rebuilding. just because a shop says yeah they can do it, does not mean they can do it right. they need to prove to you somehow they can do that type of work. and don't think taking it to a gm dealership is an answer, at best they can source a new rear end and swap them don't expect a mechanic there to be knowledgeable in the internals of the rear axle.
to fix the rear end properly, you need to
- get a new ring & pinion gear set, preferably a genuine gm gear set.
- all new bearings and seals
- a new pinion yoke, do not reuse the existing one.
- have your existing axles checked for straightness, replace if necessary.
- have you existing differential inspected for problems, the torsen has been known to break internal gears under abuse. normally you can reuse the existing differential but if not tack on $500+ for a new limited slip one.
i'm in CT. given parts and labor don't plan on less than $1000 for a complete rear axle rebuild. labor alone for a ring & pinion replacement is about $500.
getting a rear axle with an open differential... the one tire fire... don't be so quick to knock it. if you only want the car to cruise and drive normally, on pavement, 95% or more of the time you won't notice the difference. open diffs are more simple, less weight, rarely fail.
you need to shop around for repair shops that are competent in rear axle rebuilding. just because a shop says yeah they can do it, does not mean they can do it right. they need to prove to you somehow they can do that type of work. and don't think taking it to a gm dealership is an answer, at best they can source a new rear end and swap them don't expect a mechanic there to be knowledgeable in the internals of the rear axle.
to fix the rear end properly, you need to
- get a new ring & pinion gear set, preferably a genuine gm gear set.
- all new bearings and seals
- a new pinion yoke, do not reuse the existing one.
- have your existing axles checked for straightness, replace if necessary.
- have you existing differential inspected for problems, the torsen has been known to break internal gears under abuse. normally you can reuse the existing differential but if not tack on $500+ for a new limited slip one.
i'm in CT. given parts and labor don't plan on less than $1000 for a complete rear axle rebuild. labor alone for a ring & pinion replacement is about $500.
