2005 BMW X3 TRANSFER CASE REBUILD -DIY
 

This weekend I rebuilt a friend's 2005 BMW X3 transfer case. BMW wanted to charge her over $3000 for a new one. I bought the bearing kit from cobra transmission $98 and the new chain $89 from american power train warehouse. All in it cost just over $200. Don't know if it'll help anyone out or not, but I figured I'd post it.

https://www.youtube.com/watch?v=AzhznwiSLBA


Thanks,
Sean

Thanks for doing the video Sean. Wish you had a camera stand & could of shown the actual disassembly & assembly, but GOOD Job. What gray sealant did you use?

I used Permatex Ultra Grey.
Also, as far as the dis assembly. It's really quite simple. There are a few snap rings and that's it. If people take on this job, I would recommend you go out and buy Lisle heavy duty snap ring pliers. They'll make your life a lot easier and really make the job easier.

Can I assume all bearings are pressed in place & need a puller to remove & bushing press to install them? What's the torque for the assembly screws?

Bearings are pressed in. You can pound out the shaft with the input bearing on it. same with two others. They all came out very easily. If you need to, buy the 12 ton bearing press from Harbor freight then return it after you press in the bearings.
Torque for the screws is bottom them out then a quarter turn. (this is from the guy in LA who rebuilds these transfer cases) There are no torque values listed anywhere.

Hello Sean - I am trying to troubleshoot my ATC400, and wondering should the assembly at timepoint 3:59 allow the input shaft from the servomotor to rotate a full 360, or should there be some resistance from the clutchpack limiting the rotation? I've replace my servomotor and ECU, get the TC still will not calibrate. Debating if I'm going to drop the TC or just send the car down the road. Great video!

Somewhat same as above. Thanks for posting[emoji106] by doing so...youve helped many others...this means good fortune for you and your car[emoji41]

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I may have similar issue...did you ever resolve yours?

Turns out my whole clutch pack inside was shredded. I was lucky enough to find an X3 on FB Marketplace being parted out, and picked up that TC for $100.. Swapped it out, calibrated stuff with ISTA and all was great! Took longer to drop the exhaust and drive line than the actual TC swap.

Here's a vid I did on the specific instance, so hopefully some help..

https://youtu.be/0-xZ3-8hh8Q?t=583

I don’t have a free wheeling shaft where the actuator connects, did you have a force too high code? I can turn the shaft with my hand and there is some resistance it’s not significant but it’s not nothing either.

Sorry for the delay.. - I had no codes at all on the dash, which is what was really confusing in my case, as my issues didn't match up with the standard problems owners encounter. I had slight resistance, but nothing huge. Every once in awhile, it would seem to catch and be hard to turn, but sooner or later, it would free itself and spin again pretty freely.

When I put in the new [ to me ] transfer case, I was not able to spin that input shaft, I could maybe put a very small turn on it by hand before it simply refused to budge.

For those of you with TC problem...

What was the mileage when the transfer case went bad?

What were the symptoms?

My friend has a 2004 X3 2.5i auto with 165K, well-maintained.

Today the noise is nasty somewhere near the transfer case when driving at 20-30 mph, especially when braking.
Front driveshaft looks good.
Front axles look good.

Where does everyone buy your TC these days?
New is > $2900 at dealer for PN 27103455133!

Can anyone educate me the difference in symptoms of: bad plastic gear vs a kaput transfer case (bad chain, bearing and/or clutch)?

Water can get into the cargo area due to clogged sunroof drains. This happened to be back in January 2021 and caused the transfer case to go into failsafe mode (permanent 4wd, hard to steer) and of course the trifecta of ABS, brake and 4x4 lights were all lit.

It took me a while to diagnose this issue because I had recently replaced the transfer case actuator, some front suspension arms, got an alignment and replaced one rear wheel bearing so I was always suspicious about these repairs causing other problems, I was wrong...

I was able to get the transfer case to 2wd by applying 12 volts into the actuator motors' cable at the transfer case controller (VTG ECU) and then disconnected it. Drove the X3 on 2WD for 4 months. I bought the BMW 1.4 scan tool and was not able to diagnose the culprit. Finally I downloaded INPA and got a cable from Ebay. This software has an actuator and VTG ECU test function, there was no communication with the ECU so I bought an used one from Ebay for $50, replaced it and voila! it works again.
I took apart the old ECU and to my surprise I found out it's not water tight so water got it, corroded everything and created a short circuit.

So...what happens next? What did you yo do to get your solution?

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Transfer case is now working fine. This was an electronic problem solved by using INPA / ISTA and buying a $50 ECU on ebay. The whole troubleshooting journey was interesting.