4x4 flashing yellow and car bucking

[Lynda]

My 2010 X3 (standard transmission) started flashing the 4x4 in yellow and the car would start bucking.  It only last a few seconds each time it happens.  This happens occasionally when in first gear and pulling away from a traffic light. At first it threw a lot of codes and my mechanic replaced the transfer case motor and it was fine for a few weeks and it started again. But only very occasionally. Has anyone else had this? Can you tell me what i need to tell the mechanic to check? It is no longer throwing codes so he doesn’t see what the issue is and since it only happens occasionally i can’t get it to do it when we are driving it together

[Greydog]

Hi Lynda

Welcome to the Forum

The symptoms you describe are classic transmission wind up. The cause is almost always mismatched tyres so check that tyres are (A) Correct sizes for your rims (B) If tyres are correct and in good condition then it could be that the Transfer case fluid needs changing 

If he changed the the transfer case motor BMW advise the Fluid be changed at the same time.

Hope this helps

Happy Christmas

Dave