Sorry guys, I never got a notification on the replies.

To make a long story short, I bought this car from the second owner sight unseen. He claimed a new transfer case was installed as a selling point.

The car was purchased to do a cross country drive with the family and then sell. After putting 10k miles on it, I decided I want to keep it.

300 feet after I picking it up the three lights went off, brake/airbag/4x4. I suspected the guy was having problems and unloaded it on me. No big deal as the car was in really good shape otherwise.

I changed the steering angle sensor, that took care of a couple of lights. But since I had the vibration and I was 4k miles from my house I decided to disconnect the 4x4. That took care of a really bad vibration, but there is the faint one on decel that persist.

Once I got home I went through the whole car. The transaxle is definitely new, but I am sure the shop did not reset the adaptions. The center support bearing is new. Underneath the car looks like it has 5k miles, everything is perfect. I also inspected all 4 axles, which are in perfect shape. I changed the fluid in the transmission, but never did the transaxle.

From digging through Carfax and some research, I believe the first owner had the transaxle swapped for a rebuilt one. The second owner bought the car and kept it for 4 years but barely drove it, probably 3k miles in that period. So I would guess when I bought it, the tcase fluid had 5k miles and 5 years max.

I know I can go ahead and buy the fluid, but I am 100% sure this is not a fluid problem but a mechanical issue. I just dont know if its the tcase or the transmission. I am very mechanically inclined and very well versed in BMWs. Not afraid of removing the tcase, just dont want to take it apart when I am not sure whether its the problem or not.

My next step was to contact Cobra in central Fl and see if maybe I can bring the tcase to him or if he has any ideas as I am about 2 hours away.