Weird vibration when accelerating through curves

[epj3]

While accelerating from 40MPH through a 90 degree turn (Obviously big enough for a sloppy-old-suspension E30 to go 40mph through) in third gear, there is a pretty loud "grinding" noise. It almost sounds like an exhaust leak from the rear, its that loud. You can feel it through the car. It's coming from under the car and sounds like the rear. It goes away immediately when I'm out of the curve.

I replaced the clutch last weekend and I know the driveshaft went back together about 2 splines off from where it was before (Was marked from when I replaced the center bearing over the summer which I did put it back together correctly). I know I should've taken it back off and re-aligned it, but it wasn't off by much.

Anyways, under hard straight-line acceleration I can feel a slight vibration throughout the car - but it's very small and goes away before I shift to third gear. It did this after the CSB replacement (which I THOUGHT I put the driveshaft back together correctly, It sure looked like my lines were aligned).

I'm replacing the oil in the differential fluid tomorrow with the redline oil + the GM additive that was reccomended to me to take away the clutch noises in the final drive. It really sounds louder than the differnetial and doesn't sound like it's from back there.

Any Idea's? I'm REALLY hoping its the drive shaft. I'm going to be ripping the exhaust off again sometime during christmas break to replace the ENTIRE exhaust. So the driveshaft will be easily accessible.

 

[Chesty Bonds]

If you're sure it isnt the diff then the next thing i would have a look at would be the half-shafts since the vibration is more pronounced through the curves. I'm not entirely sure though...

Hey maybe you can rip off my exhaust at christmas too? Perhaps you could shout me a completely new system also...? It's my unispiring BMW muffler you see.

 

[Jon_E36]

Epj took me for a ride, and I'm not quite sure how to describe it, but it almost seems like a wheel bearing vibration, but not really the grinding like a bearing, or something that's vibrating a lot getting in contact with the body. Its hard to really pinpoint it when you're flying around sharp turns at 65mph.

 

[epj3]

Epj took me for a ride, and I'm not quite sure how to describe it, but it almost seems like a wheel bearing vibration, but not really the grinding like a bearing, or something that's vibrating a lot getting in contact with the body. Its hard to really pinpoint it when you're flying around sharp turns at 65mph.

Hehe. The only thing that keeps me from thinking its a wheel bearing is that you never hear any weird sounds going through a corner the same speed but without accelerating. Also it makes the noise turning in both directions (Jon - I figured this out by turning left at the green house going towards the highschool instead of turning right...hehe... thats what, a 25? All I know was rpm's were fairly high in 3'd gear...)

 

[Chesty Bonds]

Could be that the driveshaft is fouling on a part of the car's underbody. Get underneath and have a look to make sure. After that, well, i would still check the half-shafts.

 

[epj3]

Could be that the driveshaft is fouling on a part of the car's underbody. Get underneath and have a look to make sure. After that, well, i would still check the half-shafts.

There's no way the driveshaft could touch the body. It's hend in place by a center bearing.

 

[Chesty Bonds]

If one of the guards is bent from when you worked on your car then it will foul and (perhaps) vibrate.

 

[epj3]

I'm REALLY hoping its not a wheel bearing. Thing is, the rear end is SILENT when driving straight.

 

[mjbst111]

wheel bearings are so easy to check, so you could rule it out quickly.

Jack up each tire and try to "steer" the car back and forth. try to shake the wheel like push the front and pull the back, back and forth violently. If it does move then you have a bad bearing. gosh sometimes its so hard to explain some things on this forum.

Anyway, when i put in my new clutch, i very quickly destroyed my center support bearing. I replaced it and it still shook bad. Ended up being a universal joint and i had to buy a new drive shaft for 300 dollars because they are not serviceable. I was also told that if your drive shaft is off by one notch you can get shakes. (wasn't the case for me but could be for you)

You can pull out your driveshaft without taking off the entire exhaust. but when you do pull your driveshaft also check your universal joints. If they are slightly difficult to move it will cause shakes under acceleration.

mine shook the worst under acceleration up-hill. (it shook so bad though i didn't want to drive the car)

 

[xLibelle]

i believe it has to do with all of your rear bushings.
when you turn hard, you roll the body to the side of the rear subframe AND reposition the rear differential under the biased torque. taking these factors into consideration, and the new CSB, thats a pretty good angle on the universal joint, so you might want to take a good look at that.

 

[epj3]

i believe it has to do with all of your rear bushings.
when you turn hard, you roll the body to the side of the rear subframe AND reposition the rear differential under the biased torque. taking these factors into consideration, and the new CSB, thats a pretty good angle on the universal joint, so you might want to take a good look at that.

Well, I think it's the fan shroud that is loose. Sounds like such an easy fix to a potentially BAD problem. Who knows. I'll check it tomorrow, but the wheel bearings are definitely good.