weird drivetrain noise - United Bimmer Community

**maximk2** · 03-22-2008, 01:38 AM

Hey all.

I recently put in a set of K-sport control pro coilovers and daamn they look good! The ride is of course not as good but the car is sooooo low! I been driving it for a little over a month, and I can't even go over speedbumps. such a pain.

Anyway, today something weird started happening. When i gun it (pedal to floor and rpm's to 7) there is a vibration coming from the rear of th vewhicle. This happens between 4000 and 6000 RPM's mostly (due to high power going through drivetrain). Does it alot in first gear, almost as bad in second and in third is hardly noticible. In fourth and fifth pretty much inexistant. I was thinking that it's probably my diff (I do have an LSD because my 325i is a Canadian one, and incanada we get LSD's). Also could it be the boots that go from diff to wheel?

Vibration is violent and is making me drive slow now. I don't like it. SOmeone plz help.

PS: For mods I have a SPEC SStage 1 clutch for M3 and a fidanza lightweight flywheel (also obviously for an M3).
Engine is stock. DINAN chip and catalytic converters have been cut out (HAHA NO EMISSIONS TESTING IN CANADA SUCKERS)

**JetBlack328i** · 03-22-2008, 10:54 PM

have the rear shocks come off? or loose?

**maximk2** · 03-23-2008, 01:09 PM

nono the chocks have been doube checked and its not bumps that cause the vibration. I talked to a few people and they are telling me my LSD is probasbly starting to go. First thing to do in that case is change the fluid, but thing is that LSD fluid never has to be changed, and my bentley manual says i need BMW SAF-XLS. i doubt wal-mart would have any. I will have to wait till tomorrow for the dealership to open up.

If that doesnt help, ill have to probably get a Quaife Limited Slip Differential from bavauto. Or maybe find another LSD off a crashed E36 in a junkyard. For some reason the e36 is the most crashed car in our city. Probably because idiots like me drive them.

**mullethunter3** · 03-24-2008, 04:05 PM

I'd say it's most likely your LSD. Is this in straight line acceleration or in turning?

nick_318is · 03-24-2008, 06:38 PM

If it is under turning and or acceleration, have you made sure you're not rubbing your fender? As far as the diff goes BMW says that its lifetime for the oil but in reality it should be changed after some time. You might try finding some redline or similar to put in as the BMW stuff you will have to get from a dealer. You can also look for some redline or royal purple diff oil i think you would be looking for a 75W90, it might be slightly more but I know many who swear by these fluids.

**maximk2** · 03-24-2008, 09:29 PM

the vibration happens in straight line while accelerating. Everything is perfect when im popping a u-turn. Basically only happens when theres stress on the drivetrain. As far as I know a bad LSD will lock up on turns, so this drives me to think it's not my LSD. Last night I inspected my drivetrain, and found this on the rubber thingy holfing the driveshaft to the tranny:

it is probably not causing the noise, but i should brobably get that changed out.

**maximk2** · 03-24-2008, 09:30 PM

PS- could the CV boots or something other than LSD be causing the vibration?

nick_318is · 03-25-2008, 07:35 AM

That might be off balance causing you the vibration at a higher speed, like an out of balance wheel. Its part number 1 in this diagram:
http://www.realoem.com/bmw/showparts...05&hg=26&fg=10

**maximk2** · 03-25-2008, 06:16 PM

yeah exactly it could definetely put thje driveshaft out of balance, BUT vibration happens only in acceleration.

**xsperf** · 03-25-2008, 10:40 PM

thats your guibo, it will continue to get worse and worse and then you will have to replace it

**MBD506** · 03-26-2008, 08:37 AM

where's what a newone looks like

**maximk2** · 03-26-2008, 06:31 PM

yeah man it totally is. You can even see in the pictures i took where the bolts holding the guibo hit the sides of it, causing the vibration. my buddy pointed thaty out last night over a bottle of vodka.

im just gonna see if i can steal one from a junkyard, but i dont think one off a e30 will work, so ill have to findd a junkyard with e36 which is quite hard in this city.

**acelnah** · 11-15-2010, 10:05 AM

If it is not your gublio then it is your rear breaks. Had vibration under acceleration and while turning like rumble strips. Changed my rear breaks, fixed the problem. They were not completely worn out yet, but fixed the rumble problem.

**xuxumi** · 12-20-2010, 02:11 AM

Looking great work !