I was getting some severe gear wine from my 1.6 VLSD differential after a healthy 270k+ miles. Time to replace it, no problem there.

I got a 4.10 Torsen out of a 94 with ~60k miles. I installed the differential and axles along with some new wheel bearings as a bit of preventive maintenance. Seals all sealed well. a little play in the stub shafts but nothing abnormal and a nothing seemed wrong with the pinion play.

After installing the differential I noticed a huge drivetrain vibration, almost as if a wheel was majorly out of balance. The vibration is related to both load and speed. It starts as low as ~10-15mph and I didnt feel comfortable taking it much higher than 50mph.

My 1st thought was the driveshaft so I tried replacing that with no success. I also tried tweaking the pinion angle of the transmission and re-torquing in the event that it was misaligned. still no improvement.

The strangest part is the vibration will stop entirely at any speed if you clutch in and take load off the drivetrain.

I am running out of ideas. any thoughts would be greatly appreciated. Im pulling my hair out at this point.

 

I know it only has 60k, but I would suspect the diff needs a rebuild. I would drain the oil in the diff and look for metal shavings.

 

I'm thinking the same thing. The first thing I did was a fluid change. The fluid was free of any notable metal chips however the fluid seemed very low viscosity compared to your typical 75-90 gear oil.

Possibly a problem with backlash. But for the amount of vibration I would suspect some severe other symptoms.

 

Put the rear of the car on jackstands (not a jack), crank it and put it in gear. Then you can get close enough to figure out what's off. A mechanic's stethoscope or a long handled screwdriver can really help.

Edit: You didn't accidentally get the left side and right side axles swapped with each other, did you?

 

I had this same thing happen to my Tundra and it was the rear bearings.

 

Make sure the balance weight is on the pinon side of the diff. It's kind of a four lobed shaped thing behind the flange the driveshaft bolts too. I had a friend get one once that was missing it. Not sure that would be a big enough issue though but worth checking.

 

Lots of people remove those for weight savings, it shouldn't cause this issue.

It's most likely bearings on one side or both, as it goes away when you take load off the diff. Stop driving it!

 

Elevate your car.

 

I had a similar problem when I replaced the diff housing on my 97. It ended up being related to a bad axle CV joint. I didn't experience the noise till higher speeds, but it sounded similar to what you are describing.

I was able to stick the car on jackstands and use a mech stethoscope to listen to the diff and hubs. You can isolate the sounds to the diff housing (drive shafts, either axle or diff itself) and then take a listen at the hub side of the axle too.

Did the replacement parts come out of a running 94?

 

I found the issue. I bought a "Torsen" diff from Turbo94MX5. I bought it on faith, and it turns out it was infact an open diff, but I didnt find this out until later when I pulled the stub shafts.

But as an added bonus one of the CVs was missing 3 of the 6 ballbearings. That is what was making the lovely vibration.

I really got F***ed on that deal, so if anyone has a torsen they are willing to sell im still in the market.