I'd say it might be the center bearing of the rear driveshaft... That can cause the symptoms described and is often overlooked.

hmm i'll mention it to the mechanic, cant seem to find that centre bearing on realoem, is there just one flex disc on these x5's? cheers

One for the front, one for the rear. The rear would be the one to give problems, but not a common problem at all. A worn flex disc (also called guibo joint) usually causes harsher feel in shifts, but as I said, not common on E53's. The center support bearing on the other hand can cause what you described.

They're both on this page in realoem.

RealOEM.com * BMW E53 X5 4.4i Drive shaft, single components, 4-wheel

cool thanks for that, appreciate it, i can see the flex disc in the diagram but struggling to see the centre support bearing, which number on the diagram is it? thanks

#8

Okay, after much a lot of investigation by the dealer...they are proposing a few things.
one, they say my rear suspension bushings are shot. They suspect the left drive axle is also slipping, but are unable to determine. For now, they recommend replacing the lower control arm bushings and the lateral links, and then getting it aligned. Then, see if that fixes the vibration. If not, we move onto the drive axle, and transmission and transfer case.

They want a rather egregious amount of money for suspension work, so I'm going to go talk to them tomorrow. I would prefer to buy parts, and have them install them (I presume that if the vehicle leaves their property my warranty will be expired, because warranty technically expired last friday). That's understandable. Instead of just doing the couple bushings they recommend though, I'd rebuild the entire rear suspension. Everything rubber will get replaced.

So...that list becomes... upper and lower control arms, two ball joints, two lateral links, two guide links, two front differential bushings, one rear differential bushing. So...if possible, I'll get them all of those parts by Monday, and then see where things go.

I have their loaner car, which is a nice Z4, but I *really* miss my X5. I simply adore that thing.

I'll keep this thread updated as progress continues.

thanks for help weasel, i'll speak to my mechanic about and see what happens! cheers

Okay. Update on this issue.

Replaced rear suspension this week.
RealOEM.com * BMW E53 X5 4.4i REAR AXLE SUPPORT/WHEEL SUSPENSION

This included both lower control arms, ball joints, integral links, upper control arms ( 06, 11) in the diagram.

Ordered aftermarket axle to replace right rear - didn't like it at all - housing was thicker, only 4 threads going into diff case instead of 8 threads like the bmw axle, and the flange on the differential side was different. Decided to order OEM axle and use that. OEM axle has not arrived.

Thusly - with all new rubber, the vibration is still present. No change.

Next week it gets the new axle (soon as it arrives). Then at the end of the month it gets new subframe bushings. I really think this is either axle or transfer case. We'll figure it out, but I think it's axle. It's coming from the rear, but only when under load - either acceleration or deceleration. I'll keep this thread updated...

any update yet?

After replacing the entire rear suspension, the rear driveshaft, tires, and a bunch of other stuff, I found a mechanic who actually diagnosed this problem, and it turns out it's the rear differential. The carrier bearings in the differential are bad.