[hassmaschine]

this is on our 2006 325xit 6mt - At low speeds, when turning sharply it feels like something in the drivetrain is binding. Every once in a while I can hear a click or pop. It's not really a good feeling - I don't think my wife has noticed it, but I'd like to fix it before it gets worse or breaks something else.

Initial thought would be CV shafts - car has about 110k on it, not super high mileage. However, when CV shafts go I've usually noticed clicking sounds even when going straight. When going straight, there's no issues. I'm not confident this is the cause, although it would be the easiest fix.

Second thought would be the front diff. It doesn't look like there's a cover or anything I can open up to look inside unfortunately, but I've heard of broken front diffs on these cars before.

the AWD itself seems to be working fine and there aren't any error codes. No issues with mismatched tires or anything either.

[hassmaschine]

found this thread:
http://www.e90post.com/forums/showthread.php?t=1221582

What's the recommended fluid for the transfercase? I doubt it's ever had a fluid change. going to try swapping the fluid and resetting the adaptations. Hopefully INPA is capable, I'll have to look into that..

[ucdbiendog]

You are only supposed to use the BMW transfer case fluid in these. When i changed mine, it got rid of a similar sound you are describing at low speed turns.
https://www.ecstuning.com/BMW-E90-33...ase/ES2515438/

[matteblue3er]

Pull fuse 20 or 26 to disable the AWD system. Pulling this fuse will also disable all other safety features, including ABS. You have no wheel speed and thus no road speed. Toms of other errors but once you replace the fuse, they will all go away, but they will store shadow faults.

By removing engine load from the front wheels, it may help determine the cause of your issue. Typically, if there is an issue with the transfer case or front diff/driveshaft/half shafts, the issue will go away or lessen with the front end disabled.

[hassmaschine]

Originally Posted by ucdbiendog

You are only supposed to use the BMW transfer case fluid in these. When i changed mine, it got rid of a similar sound you are describing at low speed turns.
https://www.ecstuning.com/BMW-E90-33...ase/ES2515438/

looks like SAE 75w GL4 with a BMW logo on it. That is helpful though, thanks. I think I might already have some.

[hassmaschine]

Originally Posted by matteblue3er

Pull fuse 20 or 26 to disable the AWD system. Pulling this fuse will also disable all other safety features, including ABS. You have no wheel speed and thus no road speed. Toms of other errors but once you replace the fuse, they will all go away, but they will store shadow faults.

By removing engine load from the front wheels, it may help determine the cause of your issue. Typically, if there is an issue with the transfer case or front diff/driveshaft/half shafts, the issue will go away or lessen with the front end disabled.

I might try that. If it was the CV shaft, then it should still make noise.

[matteblue3er]

Originally Posted by hassmaschine

I might try that. If it was the CV shaft, then it should still make noise.

When my front passenger side, inner CV joint failed, I only had vibration/a thumping noise under load, ie accelerating.

After a 1 hour trip from NJ to Philly, I had a severe vibration under light acceleration and did not want to drive it any further, risking mounts/bushing from being torn.

Removing the fuse COMPLETELY eliminated the vibration/noise until I was able to slap a new half shaft in there. When I pulled the old half shaft, the inner bearing, outer races just fell out of the diff lol

[PhaseP]

Originally Posted by hassmaschine

looks like SAE 75w GL4 with a BMW logo on it. That is helpful though, thanks. I think I might already have some.

It is special oil for transfer case. The transfer case is couple grands, why risk it for $40 dollars save for the next 5~10 years?

At least look at something like this, it has the same TF 0870 Shell spec, with a deep discount:

http://www.rmeuropean.com/Products/0...Fc8lgQodI3YDeg

And scratch that TF 0870 is not enough looks like, because even Fuchs on their website saying to use the BMW oil in that transfer case:

http://fuchs-eu.lubricantadvisor.com...299407d9797c85
excerpt:

Transferbox
Capacity: Capacity 0,52 liter Initial fill
Use: Normal
Products: Special product, please use the original OEM part