Differential whine?

[jayjpl]

Had my diff checked, fluid replaced, pinion seals done, but when i accel I get a pretty annoying whine, same with deceleration. It makes daily driving kind of annoying.

Any solutions? Diff rebuild entirely?

[ATB88]

What bushings are you running? I've heard of this happening with poly.

If your bushings are stock, it may be your pinion bearings. A couple of years ago when I was new to wrenching I went ahead and re-did my pinion seal. Unfortunately, because returning the pinion nut to its original position just didn't seem tight enough, and I am very dumb, I tried to tighten it another full turn past what it should have been. This ended up ruining the pinion bearings within a few thousand miles, and I was getting an annoying hum/whine on accel and decel. New pinion bearings fixed it. Expensive job, though, and frustrating because it's actually becoming pretty hard to get one of these diffs rebuilt without shipping it off somewhere. I phoned a ton of places in/around LA and only found two people willing to do it. Everyone else (including lots of "M speciality shops") said it's just too tricky to get right for the amount of labour they would charge, therefore not worth it for them.

I hope it's not your bearings!

[jayjpl]

What bushings are you running? I've heard of this happening with poly.

If your bushings are stock, it may be your pinion bearings. A couple of years ago when I was new to wrenching I went ahead and re-did my pinion seal. Unfortunately, because returning the pinion nut to its original position just didn't seem tight enough, and I am very dumb, I tried to tighten it another full turn past what it should have been. This ended up ruining the pinion bearings within a few thousand miles, and I was getting an annoying hum/whine on accel and decel. New pinion bearings fixed it. Expensive job, though, and frustrating because it's actually becoming pretty hard to get one of these diffs rebuilt without shipping it off somewhere. I phoned a ton of places in/around LA and only found two people willing to do it. Everyone else (including lots of "M speciality shops") said it's just too tricky to get right for the amount of labour they would charge, therefore not worth it for them.

I hope it's not your bearings!

Poly bushings for both differential and subframe

might be that, i’m hoping its not the pinion bearings!

[ATB88]

Ah, yeah, it's almost certainly your diff bushings then. Poly subframe bushings aren't a problem from what I understand. Not sure if it's the rear or front diff bushings that cause the whine, or if both contribute. I'm sure plenty of members here can tell you. To go back to stock on the rear bushings you have to replace the whole rear diff cover, unfortunately. Replacing the front diff bushing is much cheaper, but pressing the OE bushing into the subframe is kind of a bitch. But both much better than paying for a rebuild!

[heinzboehmer]

I've got poly diff bushings and yeah those are definitely the cause of your whine. As ATB88 said, either purchase a new rear diff cover or live with the whine.

[Sharocks]

Poly will do it, types of fluid can do it as well. You running OE stuff?

[TylerBrown]

My poly diff bushings whine around 70mph.

[Syfon]

Poly diff bushings transmit a heap of whine to the cabin. I'm running solid aluminium subframe bushings but oem diff bushings. Barely hear any whine in the cabin. Mind you, my exhaust isn't exactly quiet

[hemi6]

The diffs in these cars are only good for about 150k, how many miles on your car?

[Obioban]

The diffs in these cars are only good for about 150k, how many miles on your car?

This is not correct.

[Tbonem3]

The diffs in these cars are only good for about 150k, how many miles on your car?

The diff is bomb proof. The LSD, however, will wear out before 150k at which point you'll have a peg leg.

[Stock_E46_M3]

What bushings are you running? I've heard of this happening with poly.

If your bushings are stock, it may be your pinion bearings. A couple of years ago when I was new to wrenching I went ahead and re-did my pinion seal. Unfortunately, because returning the pinion nut to its original position just didn't seem tight enough, and I am very dumb, I tried to tighten it another full turn past what it should have been. This ended up ruining the pinion bearings within a few thousand miles, and I was getting an annoying hum/whine on accel and decel. New pinion bearings fixed it. Expensive job, though, and frustrating because it's actually becoming pretty hard to get one of these diffs rebuilt without shipping it off somewhere. I phoned a ton of places in/around LA and only found two people willing to do it. Everyone else (including lots of "M speciality shops") said it's just too tricky to get right for the amount of labour they would charge, therefore not worth it for them.

I hope it's not your bearings!

Thanks for the Intel