Hello,
I have a 2007 BMW X3 with 102K miles on it (primarily highway driven), and a mechanic diagnosed the transfer case as bad. Basically, when the car goes over a speed bump and a hard right turn is taken, a "bump" is felt for the passenger. The mechanic showed me this issue since I wasn't aware of it. However I find it hard to replicate this scenario, and the car feels normal both on highway and city, and there are no fault codes in INPA (the mechanic also said there are no fault codes, but it's a mechanical issue.) At first the mechanic suspected the rear differential, but after changing the fluid, checking it, and test driving, he says its fine and in good condition. He also said the front differential is in good condition. When the transfer case fluid was drained, it came out as silver . However, there were no metallic particles in it (mechanic allowed me to feel it and he also felt it), so I'm assuming water contamination? I did the tranny fluid myself, and that looked fine (although dark no burnt smell and pretty much typical drop the pan, change the filter etc.)
Also, whenever I hard corner (like autocrossing...really hard), it makes a metal on metal shriek sound and the mechanic said it could be the transfer case, or brake rotors rubbing on the backplate,etc. However upon reading:
http://www.bimmerfest.com/forums/sho...=463848&page=3
it seems the transfer case may not be the issue? The brake pad warning light is on (came on recently), so that may be the issue for the shriek noise? (I plan to change rear pads+rotors since the car is used and I can't find previous records for the rear ever being changed for rotors, only for front pads and rotors and rear just pads were done). I'm pretty sure the rear springs are in good condition (based on visual inspection)?
Basically, could the transfer case be the issue, or is it most likely just nothing and I should just drive the car like normal and just do the brake job? Any way to really test the transfer case? Should I get a second mechanic's opinion? Any other thoughts?
Thanks
Heard that the transfer case is similar to the X5...that's why i'm posting here since the X3 section has little to no activity
