Suggestion for locating WHERE driveline noise is coming from

[SpencerM3]

did you try jacking up your car and seeing if the wheels move at all to test for wheel bearings, and try jiggling the driveshaft to see if its loose for that main bearing (forgot the technical term)? Maybe try for the center support too hell worth a try.

Yea we did. Like I said, we put the rear of the car on stands and spun the driveline by hand (by turning the wheels).

The driveline defintely felt hard to turn. I should try my E36 and see how hard that is to turn for comparison.

I need to do it again and check to see if there is any play in the rear wheel bearings as well.

I'll try to get to the driveshaft but it looks like there is a huge heatshield covering the driveshaft as well as the exhaust, so that might be a pretty big job to check.

[bimmerboy12]

thats what I meant about checking the rear wheel bearings, grab the tire and jerk it back and forth with your hands at 12 and 6 position. Grab a hold of the driveshaft right by the diff and shake it as hard as you can and see (or hear) if it moves at all. You can feel even as little as .003 inches of play (at least I have).

[clavinZERO]

i think he might have meant G U I B O hehe

[christophbmw]

My 318is has a medium/low pitch wirl that starts at around 40mph and seems to be coming from the rear driver's side wheel. It's probably the wheel bearing, but I've heard that a bad flex disc (guibo) can cause drivetrain resonance in the rear shocks which can cause a similar noise.

But it's all good, since I'm switching to 5 lug from an E30 M3 w/ 50k mile parts, which probably have good bearings all around :)

....uh no that would be your fuel pump. the 318is has a problem with that and judging by the symptoms you just described i would geuss that it is your fuel pump.

[BimmerToad]

The sound is also speed dependant, not engine load or throttle position dependant.

[nando]

Re: whining

Another one of my friends claims the problem is a worn out speedo cable, a problem that originated in the 2002's.

E30s don't have a speedo cable.

the fuel pumps do make a noise, and it's louder in my friends 318is than my car. that might have to do with extra sound insulation. the diff or tranny could also make a similar noise if the fluid was low or they were going out. also, you could have a ground loop in your stereo system that would cause a noise that varied with speed, it shouldn't happen if your stereo is off though.

my car is pretty quiet, I can barely hear the fuel pump, but there is no noise from the tranny or diff that I can tell.

[la-zdunck]

I'm having a similar problem and have come up with the following.

to test if the problem is in the final drive (diff), disconnect the cv axels and run the car stationary at the same speed and same gear in which the noise/vibration is present most. If there is a noise or vibration still present, the problem is in the driveline. If there is no noise/vibration, the problem is in the cv drives, or wheel bearings. I'm no mechanic, but this might be a good way to be certain if the problem is in the driveline.

I don't think your problem is the driveshaft center bearing or whatever flex disc. When those needed to be replaced on my previous e30, a wobbling noise with vibration felt like it was directly under my e-brake handle. The noise sounded and felt just like the drive shaft was wobbling around under the car, and distinguishibly not in the rear-end.

I don't know jack about the fuel pumps, but I would love to know if that is causing the buzzing/whirring noise I hear from the driver's rear when the engine is running and the car standing still.?

I hope this helps, as I will be trying this lil test and hope to diagnose my own not-so-good vibrations.

[SpencerM3]

I'm having a similar problem and have come up with the following.

to test if the problem is in the final drive (diff), disconnect the cv axels and run the car stationary at the same speed and same gear in which the noise/vibration is present most. If there is a noise or vibration still present, the problem is in the driveline. If there is no noise/vibration, the problem is in the cv drives, or wheel bearings. I'm no mechanic, but this might be a good way to be certain if the problem is in the driveline.

I don't think your problem is the driveshaft center bearing or whatever flex disc. When those needed to be replaced on my previous e30, a wobbling noise with vibration felt like it was directly under my e-brake handle. The noise sounded and felt just like the drive shaft was wobbling around under the car, and distinguishibly not in the rear-end.

I don't know jack about the fuel pumps, but I would love to know if that is causing the buzzing/whirring noise I hear from the driver's rear when the engine is running and the car standing still.?

I hope this helps, as I will be trying this lil test and hope to diagnose my own not-so-good vibrations.

Thats actually a really good idea. :D

I'll have to give that a try this weekend.

Thanks.

[SpencerM3]

Went ahead and did it right away... ;)

Disconnected the half shafts and ran it though all the gears up to about 100mph. No noises from the driveline....

So it seems that its either the wheel bearings or CV joints. I did noice that all the CV joint boots are starting to crack and the driver side outer boot has a small tear in it. So its time to replace the boots.

I'm about 90% sure its the wheel bearings. Everyone I talk to says that wheel bearings start to make noise at about 30-40mph which is exactly when the noise starts to come in.

Thanks again for all the help guys....