Transfer Case went to S!@#
 

So to keep you guys up on it.
Apparently this does happen often.

My transfer case failed. I was able to catch it early on but there is a need for a new unit.

My car:
2008 4.8i with (almost) 160K on the clock.

Things to watch out for are loose shafts from the Transfer Case.
Apparently if they fail when you drive they will take out your transmission and possibly drive axles.

Pic just because:
http://i172.photobucket.com/albums/w...psbj9xavmc.jpg


UPDATE: 2016/02/25

Finally fixed.
It took about a month.

The case was shipped to a firm in California.
Got a fully rebuilt Transfer Case and Front Drive Axel.

Cost: about $2700.oo for all (labor, rebuild and shipping)

What were the signs or symptoms of failure?

I initially notice some fluid under the car... but it happened at the same time one of coolant pipes went (so I did not pickup on it).
The fluid I noticed seem to be fine and clear.

As for how I determined there is something wrong:
- cost the car from 15 miles/hr, 10 miles/hr and 5 miles /hr to stop and listen to a clicking sound like if a wheal drive axle is failing.
- while costing car put it in neutral gear and observe no change in sound
- while costing turn wheels left to right and observe no change in sound

Parts are ridiculous.
- transfer case: about $2800
- front drive shaft: almost a $1000

There is a possibility to rebuild those parts (I'll try to post that contact info here later)

One SWEET Looking X5 Gregg3gs...!!! :wow:

Really? At 160k?

apparently earlier.

Thanks "95wildtt", check out the link bellow.
Pics are about half way down the page.

http://www.xoutpost.com/bmw-sav-foru...thread-72.html

UPDATE:

Finally fixed.
It took about a month.

The case was shipped to a firm in California.
Got a fully rebuilt Transfer Case and Front Drive Axel.

Cost: about $2700.oo for all (labor, rebuild and shipping)

Was the fluid ever changed?

Although BMW does not offer parts, the TC (as well as everything else in this world) can be rebuilt. May not be for everyone, but for those of us brave enough, a good source of parts is Cobra Transmission -> https://cobratransmission.com/ I'm sure there's others, these are just guys I know and carry parts for both the TC (ATC700 in my 35d -> https://cobratransmission.com/index....x&cPath=3_2230) and the the ZF transmission (ZF6HP26Z in my 35d -> https://cobratransmission.com/index....1495_1497_1608)

Perhaps is just a couple of bearings which as fairly inexpensive...

I've always wondered how many of these issues are due to failure of the plastic gear that's used to load the clutch pack.

I started to hear a noise similar to what you're describing after I replaced my thrust arms, but didn't really pay attention.

Does the sound seem to come from a certain side, driver's or passenger's?

the "pop" or empty like metal sound comes from front passanger side. It's almost like coming from front axcel.

Do a quick test.
Get under the car and locate where front drive shaft goes into an enclosure (right under driver seat area.)
Move the shaft up and down. You should have very little play. My had about an 1" of travel.

The noise I'm hearing definitely comes from the driver's side. I looked to see if I could locate the driveshaft under the drivers seat, but I couldn't see anything that I could reach without jacking the car up. I will try again the next time I change the oil. Btw, I just turned 80k, so I'd like to think it's too early for TC problems, but who knows.

Look for a cross member under the car.
Locate front drive shaft (between front axle and transfer case)

2008 BMW X Series (E53,E70,E71,E83) X5 4.8i 4-WHEEL drive SHAFT/INSERT nut

In the image above, part #2 is where the problem is on the "U" join section.
Check for play, it is accessible without lifting the car, if you are thin enough.

Good luck.

Who knows?? I knows!
My 2012 50i is at the dealer now getting a new transfer case at 45k miles.
I noticed some "crabbing" of the wheels in tighter turns, and parking scenarios. Like they weren't all able to turn at the same speed. Then I got new tires and it seemed to go away, for a while.
When it returned I noticed, and when the vehicle went in to the dealer for some recall work I mentioned it. Luckily I have ~6 months left on my CPO warranty so it will be on BMW.

My 35D had some shudder during tight turns under power, BMW quoted $5000 or so for replacing the TC. Elsewhere in the forum I saw someone had changed the TC fluid and got reprogramming/adaptation cycle run and that fixed it. I decided to try that and luckily it worked for me too. From what i can gather the plastic gear in the actuator wears out, replacing that and changing the fluid seems to fix the issue. Her's the link to the thread.

https://xoutpost.com/bmw-sav-forums/...4bdc-4a14.html

Here is a plastic/cf blend aftermarket solution for the servo actuator gear -

https://www.ebay.com/itm/For-BMW-X3-...-/221576643880

http://x8r-instructions.co.uk/BMW-X3...o-Actuator.pdf