Weird Sound From Drivetrain?

[PorkandBeans]

There is a mechanical sound, a whirring sound, coming from my car when I’m driving. It will stop at random and all of the sudden (rather than getting more faint), sometimes for a couple days, but it’s back again. It changes pitch with the speed I’m going, higher pitch while traveling fast and lower while going slow, no sound when at a stop. Sometimes it’s really loud but the loudness is random too. Changing gears or selecting neutral doesn’t seem to change anything.

Any ideas on what this could be? It’s really cold here lately but I’m not sure if this has anything to do with it, just don’t want to be stranded somewhere.

Thanks in advance.

[StereoInstaller1]

Immediately check your guibo bolts, then get to the CSB and inspect it.

Likely as not, your u joints are taking a dump on you.

[matias88e30]

check the guibo, and the driveshaft center bearing. let me kno..

[PorkandBeans]

Thanks for pointing me in the right direction. I'm dropping it off at the shop tomorrow. Will ask for them to check the flex disc, u joints, csb, and while I'm at it will probably have the axles rebuilt or replaced since they're original boots and I saw they were starting to tear.

Anything else to replace while the driveshaft is out?

[GunMetalGrey]

U is for universal correct? cuz im getting the same thing... it seems to go away at times though, and it has been very cold here as well

[GunMetalGrey]

check the guibo, and the driveshaft center bearing. let me kno..

Do you have to drop the tranny to get at the guibo?

[PorkandBeans]

I just dropped my car off and the sound was gone the whole drive there - 10 miles. It was raining so I'm hoping it was some salt/dirt that managed to get where it shouldn't be and was rinsed away. I doubt it though. I'll let you know what my mechanic says...

[NC325iC]

Do you have to drop the tranny to get at the guibo?

no, if it need replacing you will need to drop the driveshaft (which means dropping the exhaust and heat shields)

it can be visually inspected without removing anything though, and if its not fraying and destroyed or cracked up (ie if it looks good) it doesnt need replacement

[PorkandBeans]

My mechanic said none of the driveshaft parts were in need of replacing after a physical inspection. The noise comes back occasionally but never for too long and only in sub freezing temps. He told me to stop in and give him a ride if the noise comes back for more than a day or so or if I hear any clunking. Charged me $20.

[GunMetalGrey]

Alright, thanks for the info. I will have to see what happens when it gets warmer out!

[blunttech]

dont know if this relates or not but I have an e39 540 with a bad abs sensor in the right rear. It does what youre describing and comes and goes.