rear LSD bad?

[FLYNAVY]

Gents, have been having some issues with what seems to be either the rear passenger wheel bearing or possibly the LSD, and I'm trying to narrow down the problem. Here are the symptoms:

1) Noticeable noise coming from that area of the car, sounds more like something dragging than the high pitched whine a lot of people talk about from bad wheel bearings. Has more of a rythmic pattern at low speed.

2) Car is dragging a little bit to the right when I'm driving, causing me to hold a very small amount of pressure to the left on the steering wheel to keep it tracking straight on level roads.

3) Popped an anti-skid caution the other day driving home, first I had seen of that.

It isn't real bad at this point, but I definitely want to get it sorted out as soon as possible. Tires are all normally inflated, and not interfering with any part of the car so much as I can tell. For reference, it is a '90 M3 if that makes any difference. Any help/ideas/advice would be greatly appreciated!

[u3b3rg33k]

Anti skid caution? whuzzat?

[FunfGan]

I believe he means a warning light maybe?

[u3b3rg33k]

Yeah but e30 m3's don't have traction warning lights...

[FLYNAVY]

I sorry.....ABS light on the cluster.....I think of them as one in the same, even if they really arent

[jlevie]

(1) Sounds like a bad wheel bearing or dragging brake.

(2) Sounds like mis-aligned rear wheels.

(3) Could be failing wheel speed sensor

[u3b3rg33k]

The ABS light on e30s only comes on when there's something wrong with the system (or it thinks there is). it doesn't turn on if the ABS runs for normal reasons.

[FLYNAVY]

The ABS light on e30s only comes on when there's something wrong with the system (or it thinks there is). it doesn't turn on if the ABS runs for normal reasons.

Right, I just meant that it is my assumption that whatever is causing the dragging is also causing enough of a rotation differential between the wheels to trip off the light. Anyone have a good method for figuring out if it is the diff, or a problem further down the axle line?

[jlevie]

In my experience there would have to be an extreme difference in wheel speeds to trip the ABS light. The only time I've seen an ABS warning light there has been a fault in the system.

When at a neutral throttle a pull will be from mis-alignment. Mis-algnment of the rear wheels can also cause a pull in one direction under acceleration and a pull in the other direction under decelleration. Common causes of this are a bent trailing arm, bad rear trailing arm bushings, or bad subframe bushings.

To check for a bad rear wheel bearing, get the rear of the car in the air, remove the brake pads and spin each wheel. Any noise or roughness is either the bearing, half shaft. or dragging parking brake.

[FLYNAVY]

In my experience there would have to be an extreme difference in wheel speeds to trip the ABS light. The only time I've seen an ABS warning light there has been a fault in the system.

When at a neutral throttle a pull will be from mis-alignment. Mis-algnment of the rear wheels can also cause a pull in one direction under acceleration and a pull in the other direction under decelleration. Common causes of this are a bent trailing arm, bad rear trailing arm bushings, or bad subframe bushings.

To check for a bad rear wheel bearing, get the rear of the car in the air, remove the brake pads and spin each wheel. Any noise or roughness is either the bearing, half shaft. or dragging parking brake.

Awesome, very helpful info, thanks!