[subieworx]

I have a 2014 X3 M sport with 42k miles that was exhibiting some slight vibration under heavy acceleration. Got under the car and found there to be play from the front drive shaft to transfer case connection. Normally I would expect a u joint to be going bad, but it turns out they are all fine and that the play is actually coming from the end of the splined connection of the driveshaft to the transfer case.

Has anyone seen this before and is there a bearing in the transfer that can go bad and cause this? I have no problems tearing the transfer case apart to replace a part, but want to know what parts I would need to replace.

[TheCoolX3]

Originally Posted by subieworx

that was exhibiting some slight vibration under heavy acceleration.

Now I am by no means an Xdrive expert but I would imagine there would be less power going through the transfer case and to the front axel under heavy acceleration while moving. I would imagine Xdrive would send most, if not all of the power to the rear wheels during hard acceleration while moving. I would not recommend launching your car from a stop because that will put a high load on the transfer case and potentially break it further.

I would try some low stress testing. Do some low speed turning and low speed with Light - Medium accelerations on unpaved surfaces to put some stress on the transfer case without the risk of further damaging it. Id try further diagnosing the issue from there.

Let us know the results
Best of luck!

[huntercross]

Originally Posted by subieworx

I have a 2014 X3 M sport with 42k miles that was exhibiting some slight vibration under heavy acceleration. Got under the car and found there to be play from the front drive shaft to transfer case connection. Normally I would expect a u joint to be going bad, but it turns out they are all fine and that the play is actually coming from the end of the splined connection of the driveshaft to the transfer case.

Has anyone seen this before and is there a bearing in the transfer that can go bad and cause this? I have no problems tearing the transfer case apart to replace a part, but want to know what parts I would need to replace.

Mine has the same issue. Did you ever get it resolved?

[subieworx]

Kind of. I took it apart and did verify for sure that I had wear on the splines from the driveshaft to the output of the T case. I have the ATC450 t case in mine which has a different output than the ATC400. I took the driveshaft out and rotated it 120* to get the splines to a different point of engagement. I then packed the hell of out of the t case output with a very heavy waterproof grease to take up any extra slack. After reassembling the vibration has been dramatically reduced. Good enough for now.

I also spoke with Cobra Transmission who has the parts needed to fix the problem. Basically need to replace the output on the t case and the driveshaft, but if I am going to do that I am going to do a full rebuild of the t case. I am going to wait until it makes noises to do that.