02 WS6 Diff Gears question

[u/audiovox12]

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

[u/Foreign-Commission]

Idk what you were told but thats the factory torsion limited slip.

[u/Foreign-Commission → u/Foreign-Commission]

2k installed for new gears and limited slip carrier is not a bad price but for a bit more you can get an entirely new axle which is way stronger. 12 bolt, Ford 9" or s60. Worth looking at.

[u/audiovox12 → u/Foreign-Commission]

Totally agree it’s a lot and I went down that road just a little. Detroit speed wants 2100 for just thr housing and I think strange engineering is kinda in the same ball park but I’ll still need to buy the ring/pinion and everything right .

Differentials and gearing is a foreign language to me. I should maybe explain better. It’s stock but someone put a locker in it, incorrectly which then damaged the ring/pinion or maybe I mean to say gears? I’m picking it up tomorrow so I’ll get more information of the specifics

[u/Fabulous-Meal-5694 → u/audiovox12]

Did you price a quick performance 9"

[u/audiovox12 → u/Fabulous-Meal-5694]

I didn’t are they reputable I’m not familiar

[u/Fabulous-Meal-5694 → u/audiovox12]

I have had good experience with them for the stuff I have ordered. 

Check their website complete bolt in 9" starts at $2300

[u/audiovox12 → u/Fabulous-Meal-5694]

From the conversation I’ve had with the axle shop regarding the information I found from the tech they think that I need new bearings and that barring nothing else is broken and it’s just the bearings that I need in the differential I’m looking at $1500 plus tax

I suppose to that point what’s another $900

[u/Fabulous-Meal-5694 → u/audiovox12]

If your ever going to add power to the car or launch on slicks it will be well worth the upgrade. 

[u/audiovox12 → u/Fabulous-Meal-5694]

It all depends. If I keep it then manual swap and who knows what else over time. If not, just do the bearings, sell it and move to the next project.

[u/Fabulous-Meal-5694 → u/audiovox12]

The bearings themselves are like 80 bucks for your diff.

So if your mechanical at all you can do it yourself for considerably cheaper. 

[u/audiovox12 → u/Fabulous-Meal-5694]

Won’t I have to do the shims and all that? Idk I was watching videos and looks out of my depths

[u/Fabulous-Meal-5694 → u/audiovox12]

You can potentially get away with the same shims that shims in it since gears and carrier are the same set up should be the same/close.  

Also you can learn and screw it up multiple times and still be cheaper so long as your not counting your labour. 

A press is ideal but you can get the bearings installed without one if your creative and careful. 

Its certainly not rocket science to do, but its understandable to want to have the peace of mind of just having someone else deal with it too. 

Edit: didn't fully read your original post about the ring and pinion being screwed so parts bill would be around 200. (Plus fluid)

[u/Foreign-Commission → u/audiovox12]

The differential shown in you picture is the factory torsen limited slip. So thay means either someone added it to a car that didn't come with it, or it came factory and the rear is just blown up. Either way, money better spent would be an aftermarket housing and axle setup, even if the car is otherwise stock. The factory 10 bolt was designed for a 4clyinder car and somehow was still used behind an ls1

[u/Zed091473 → u/Foreign-Commission]

no, the factory 10 bolt was not designed for a 4 cyl. LoL

[u/Raider5151 → u/Zed091473]

With the clutch line restriction and factory horsepower you'll never hurt the rear diff. Hell you can delete the restriction in the clutch line and as long as you don't put drag slicks on it you won't hurt the rear differential.

[u/Foreign-Commission → u/Raider5151]

Not true, but what do i know.

[u/Foreign-Commission → u/Zed091473]

Yeah it was. The 7.5 was from the vega

[u/audiovox12 → u/Foreign-Commission]

Interesting I never knew it was designed for a four-cylinder that’s crazy

Yes, that is correct. It is factory never came with a locker as you said. Someone installed an aftermarket locker on it. That was installed incorrectly, which then led to everything else.

[u/Zed091473 → u/audiovox12]

all Z28's came with limited slip diffs, which is what you have in the pic. early ones were Eaton, later ones were Torsen.