2000 540iT - Drivetrain creek when cold

[ddavies]

Hey Everyone,

Normally I can manage to find most my answers on the forums but alas we're here.

I did some maintenance on the ole wagon over the holidays and now I have a noise that I can't quite seem to chase down.


The "Noise"

It seems to be coming from the drivetrain, the "Creeking" cannot be felt through any of the pedals, steering wheel, or shift knob but can be slightly felt in the floor/seat.

At one point I was convinced it could be the right front wheel but now i don't think it is.

It only happens for about the first 2-4 minutes after the car is cold and never in any gear higher than 3rd

It only happens at lower speeds and when the drivetrain is accelerating, I have not seemed to notice it when decelerating.

Sometimes it also sounds like a "Halllow rumble"

I've attached a video with some captions to help call out the creek and rumble as best I can.
https://youtu.be/vrJ_mltrsVQ

Work done over the holidays

1. Removed trans and replaced all "replaceable" detents and rear shift carrier bushing

- The trans shifts HARDDD always has, which is why I replaced the detents - unfortunately did nothing to help shifting. I have a spare trans that will be going in since I thought this would be the outcome.

- All clutch parts are in great shape, they're just over a year old and have less than 6k miles on them. Cleaned them up and re-greased before re-installing trans.

- Got the car back up in the air to check over the work and all seems good. Everything is good and torqued to spec.



2. Removed, rebuilt, & painted all calipers. New pads, rotors and parking brakes

- Flushed brake fluid with Pentosin Dot 4 LV

- Flushed the the Clutch system at same time

- Nothing seems to be binding on any corners of the car when back up in the air, brakes feel great.


Common go to's
- Guibo - just over a year old and less than 6k miles
- Carrier Bearing - just over a year old and less than 6k miles
- Driveshaft CV - rebuild just over a year old and less than 6k miles
- Engine mounts are about 2 years old
- Trans mounts just over a year old and less than 6k miles
- Replaced rear main - just over a year old and less than 6k miles
- front control arms - has mono ball - replaced 4 years ago about 25k miles on them
- Front KW coilovers and OEM top hats - 20k miles
- Rear end suspension components needs a refresh but still has life in it. nothing is loose but mileage is unknown :/

I thinks that's it for anything related that could be directly related to the noises - Also im giving background on the items above but not writing them off.




Thanks ahead for any help!

[KeysCoupe]

Driveshaft is the first place I’d suspect. The rear U-joint by the diff pinion is known to get stiff with high miles/age. Also, the carrier bearing (though changed out recently) can go bad in short order if it was not correctly preloaded on installation.
-Donny

[ddavies]

Hey KeysCoupe, thanks for the suggestions!

I got under the wagon the other weekend and checked out the carrier bearing, still looked good and I reset the preload on it while I was down there. The center u-joint on the driveshaft seemed like it could have the slightest amount of play. It could only be felt when rotating the two driveshaft halves opposite each other, the play wasn't visible though. I've had much worse slop in driveshafts. Drove it again and the noise is still behaving the same.

I thought it would be easy enough to swap out the right front wheel bearing that I though was suspicious before sir also did that and put new sway bar end links one, but the noise again stayed.

The slight play in the driveshaft really wouldn't normally scare me but I'll take that out next and get all the u-joints rebuilt, not sure what else it could be.

Thanks again for the help!