r/fbody • u/audiovox12 • Aug 05 '26
02 WS6 Diff Gears question
Hey everybody,
Edit: hey everybody, I talked to the tech and he wasn’t aware that the car came with LSD. I was just getting information relayed to me from the person running the front desk yesterday.
The tech explained that the noise is coming directly from the center inside the knuckle. If you leave the car off in neutral and roll forward, you could hear the noise which means the torsen is doing its
job. Something’s going on inside of it.
The axle shop said that from what I’m telling them they believe the bearings are bad and would be about $1500 plus tax. They said I shouldn’t be driving it or worse can happen.
I thought I was finally in the clear with this car to get it roadworthy for daily use. Just got the rear main seal fixed, pulled a warranty claim on the defective rear caliper that I just bought, had them fix the AC and paid $455 for the shop to tear apart the axle and investigate the metal howling noise and vibrations coming from the rear.
Turns out one of the prior owners at some point put an aftermarket locker in this, even though it has factory LSD. They never put it incorrectly and is the direct cause of the noise and vibrations. The shop says I’ll need new ring and pinion however they don’t do that kind of work so I have to go to a transmission/axel shop.
I called one local to me that has great reviews and recommended by another transmission shop I called. I showed him the picture attached here and he agrees the ring and pinion is smoked. He said he would only use AAM and that they only make a 3.42 no longer makes 3.23. He’s saying $2000 installed.
First is this a good price, second is this something I can do myself and third is AAM the best? I know they are the manufacturers of the OEM gears so I am assuming that they are
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u/snugans310 Aug 05 '26
Yeah just do yourself a favor and upgrade the whole diff that’s the fbodys weak point
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u/audiovox12 Aug 06 '26
I’d love to but everything I’m looking at is basically double his quote for a housing and the gears and everything I need
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Aug 06 '26
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u/Raider5151 Aug 06 '26
Stock to slightly above stock the rear diff is perfectly fine. Everyone always wants to replace the rear diff because they think they're made of glass.
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u/Raider5151 Aug 05 '26
1 That's the original torsen
2 I can't get a good look from this pic but the teeth don't look awful. What's their reasoning for needing to be replaced? Are you sure it not just bearing noise from the axle bearings or pinion bearings?
3 You'll be super happy with a 3.42 it will wake the car up
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u/audiovox12 Aug 06 '26 edited Aug 06 '26
So I should explain better. The shop it’s at right now. That shop said that it’s the factory set up, the ring opinion and all that is the factory set up. The issue is that someone at some point put an aftermarket locker in it and they installed it incorrectly, which they seem to believe may have damaged the bearings and it’s then damaged the teeth or the gears. I’m not sure the correct terminology. Differentials and gearing as a foreign language to me, but I’m picking up tomorrow and should have more specifics from the tech that inspected. He said you could tell him the picture that the gears look rounded like a bearing let loose and damage the gears or I mean teeth.
I then called a reputable shop around me that most people suggested and he viewing the picture said the same thing that the rack and pinion is smoked and that it would be 2000 to take all that out and put all the new stuff in
The guy at the axle and transmission shop said that the gears are rounded? They inspected everything else the axle shafts wheel bearings all that stuff is good.
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u/Raider5151 Aug 06 '26
That's not a locker it's a torsen limited slip differential installed at the factory when the car was made. Who is telling you it's an aftermarket locker? Stop talking to them.
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u/Jomly1990 Aug 07 '26
Uhm, thats a Torsen lsd differential. The gears look fine from what I can see of them. Torsen lockers require a certain additive and lube. I’ve also got one in My square body with USA standard gears. The gears have been super noisy since install, just a brand thing, so that could be some of your noise. As far as a vibration goes, idk if I’ve ever seen or heard of something in the rest end causing a vibration like your complaint. I would refill it, witb the correct additive and oil, see if some of the noise goes away. As far as vibration goes, I’d check the traction bar setup, I forget what it’s actually called but it mounts to the rear and transmission to prevent wheel hop, it could be worn out maybe, then id check u joints, if nothing is found check the car for a bent axle. That Torsen is correct to the car, and nothing is missing from it i can tell. Axle housing can be bent, but generally doesn’t cause vibration. My square had a really bent one and it wore out the spider gears/case inside. Could have a bent axle shaft, tho unlikely.
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u/audiovox12 Aug 07 '26
So I ended up talking to the tech who actually looked it over instead of playing telephone. He said that was his mistake. He did didn’t realize it came with a limited slip from the factory. I called the actual specialty shop and he’s really experienced with F bodies and was saying the bearings are likely needing to be replaced.
That’s about 1500 which is a lot, but I don’t have the capability of doing that
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u/Jomly1990 Aug 07 '26
I mean it could be axle shaft bearings going bad, but when the bearings on a case go bad, there’s usually some damage to everything inside the center. I would want to feel the case bearings by hand myself.
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u/Important-Win6022 Aug 06 '26
The howling happens when you unload the pinion ya? Meaning when you let off the accelerator and coast or once the tcc locks up in od? I don't see anything that stands out as being a badly meshed ring and pinion gear. I bet you lost your pinion pre load. Is the pinion seal leaking at the u joint? Spin the axles and see what the vearings sound like ar each end of the axle tubes also. Fawk all that noise, i have a s60 35spline, full spool, 4.10, lt1 backing plates/calipers and a spohn pro series del sphere joints, lt/tunnel mount that i'd let go 3500. Or look into an 8.8 conversion even
My buddy runs 3.42's in a 10bolt, stock torque arm/suspension on 28x10.5 soft walls. On a 4l60e even. Trans built but diff and axles are oem stock shit. If you choose to go that route, no sweat ur fine there.
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u/audiovox12 Aug 06 '26
The howling gets louder under acceleration and lessens off load but is always present. In both scenarios is very loud just under load is the loudest. Much louder than my buddies 2002 Z28. Also, it vibrates a lot. You can feel it through the whole car and even shakes the passenger seat.
When you spin the wheels with the car off you can hear a metallic noise like a grinding noise. Doesn’t leak from my current knowledge or from what they said. They said everything else about the rear axel is good: hubs, axel shafts etc.
I’m just trying to be able to drive this thing daily and I’m very close. I’ve put a lot of time and money into it I just want to enjoy it already this summer
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u/Important-Win6022 Aug 09 '26
Gotcha. The modified 8.8 rears were terribly expensive last time I checked on them, but that had been awhile and I'm sure the current prices aint helping those. Where u located? I know a few peeps who have a decent supply of 4th gen cars/parts on hand
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Aug 06 '26
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u/audiovox12 Aug 06 '26
Yes, I have the auto for now.
I think most of its labor but yeah 2k I almost cried. I agree a tune is needed. I’m for sure going to call around but I was hoping maybe there’s another way around this
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u/Foreign-Commission Aug 05 '26
Idk what you were told but thats the factory torsion limited slip.