Another transmission/diff/transfer case problem

Hi guys,

Long time lurker...I searched and searched and couldn't find exactly a similar situation on this forum.

So my 2006 X3 developed what I would guess is the standard transmission/transfer case clunk about 3000 miles ago when it had about 90k miles. I changed out the tires to new Pirellis per BMW specs, changed transfer case fluid, transmission filter/fluid, and diff fluid, all per BMW fluid and specs. Further, I rotated the actuator gear on the transfer case per the sticky above. None of it really fixed the issue until I rotated the gear. So I figured it was definitely the actuator gear.

All of this made the issue way better, not fixed, but much much better...until about 4-5 weeks ago. The clunking got worse...bought a new actuator gear off ebay and it made the problem a little better, but not to the point when I rotated the gear. Now a couple weeks later, its as bad as ever. Further, now when I coast I get the clunking when coming up to a stop light while off the brakes. It does it while on the brakes as well. Next, I also get the clunking under low speed like off throttle in a parking lot looking for a space.

The off throttle clunking or stuttering feels slightly different than when on throttle. Sounds and feels more like it is coming from the diff and or too much back-lash in the drivetrain somewhere. The normal clunking occurs in all gears and pretty much any rpm. It is most noticeable in the 2500-4000 rpm range.

Any thoughts? I was going to take it in to get the software updated, but I don't think that is going to solve the issue. May help, but not fix it.

Might sound dumb but check your lug nuts and make sure they are tight. Otherwise My clunking was fixed with what you already addressed which were tires and transfer case fluid change.

Nothing sounds dumb at this point. I will check that. I also found another link on here or bimmerpost that talks about checking the subframe bolts to make sure those are tight as well.

I still have not done the software update...anyone think its worthwhile to spend the $150 or so to get it done?

I just posted a relevant post a couple days ago which I am guessing is where you got the subframe idea. However, I think you missed the part about the loose t-case mounts. Check this out again-
http://www.bimmerfest.com/forums/sho...d.php?t=695692

Thanks. Im going to check out that stuff this weekend. Im obviously not giving up on any ideas, but I don't have the turning the steering wheel clunking/popping.

The clunk/pop from turning the steering wheel is a completely separate issue. What I was pointing out in my post was that in the process of fixing that issue they discovered a bunch of stuff loose including the tcase mounts. And, tightening them which was an ancillary repair resulted in a nice surprise, no more clunk.