A few weeks go, my 3.73 lsd started making some gnarly clunking while going through low speed corners/driving around in a parking lot. Pretty much any low speed parking lot-like corners. Eventually it got so bad that it seemed like the diff would start to bind and almost wanted to spin a wheel. Based on the symptoms, I removed and opened up the diff, and sure enough, I found a good amount of metal pieces and broken teeth. Based on the shape of the teeth I was able to determine what gear must have been damaged, I’ll make a link to real oem in a comment to this post.
Anyways, I just got a ‘good’ 3.25 lsd from an automatic 5 series, and was promised that the diff was in good condition, and that it had been run in an e30 and traded out for a 3.46. So I swapped in the 3.25 last weekend, and after taking it around the block a few times and up the freeway to put it through a heat cycle, I started getting some noises from the rear end that sounded very similar to the noises my 3.73 started to make.
So far, I have done the following-
Removed caliper and discs from rear hub to check play in wheel bearings- there is none.
Removed parking brake assembly from passenger side (noise seems to come from this side) no change.
Checked axles for play- no play at all (at least using my hands to pull on it), only normal axial (in & out) play in CV’s.
I’m starting to think I was sold a broken diff. Is there anything I can do to absolutely confirm the diff is or is not the issue? While on jack stands, clutches seemed to breakaway smoothly (rotating tires in opposite directions), and the dull grinding/clunking noise seems to be less dependent on turning than it was when my 3.73 broke.
As of now, all I can think of to try other than throwing parts at the car, is to jack up the rear, remove caliper and discs (leaving just the hub) and start the motor in 1st to get the rear end spinning on jack stands, and listen to everything with a stethoscope. That and/or just drive the car until the noise gets worse and is easier to determine where it’s coming from- obviously not an optimal choice.
Any insight and suggestions are welcomed, let me know if I should explain something more clearly
Anyways, I just got a ‘good’ 3.25 lsd from an automatic 5 series, and was promised that the diff was in good condition, and that it had been run in an e30 and traded out for a 3.46. So I swapped in the 3.25 last weekend, and after taking it around the block a few times and up the freeway to put it through a heat cycle, I started getting some noises from the rear end that sounded very similar to the noises my 3.73 started to make.
So far, I have done the following-
Removed caliper and discs from rear hub to check play in wheel bearings- there is none.
Removed parking brake assembly from passenger side (noise seems to come from this side) no change.
Checked axles for play- no play at all (at least using my hands to pull on it), only normal axial (in & out) play in CV’s.
I’m starting to think I was sold a broken diff. Is there anything I can do to absolutely confirm the diff is or is not the issue? While on jack stands, clutches seemed to breakaway smoothly (rotating tires in opposite directions), and the dull grinding/clunking noise seems to be less dependent on turning than it was when my 3.73 broke.
As of now, all I can think of to try other than throwing parts at the car, is to jack up the rear, remove caliper and discs (leaving just the hub) and start the motor in 1st to get the rear end spinning on jack stands, and listen to everything with a stethoscope. That and/or just drive the car until the noise gets worse and is easier to determine where it’s coming from- obviously not an optimal choice.
Any insight and suggestions are welcomed, let me know if I should explain something more clearly
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