Click noise, but no lights

--------------------------------------------------------------------------------

I took my wifes car into an Independent dealer, they do minor work on BMW's. There is a clicking noise with every revolution, I thought that it might have something to do with a wheel / brake??

The meachanic said that when on the rack and with the drive shaft turning, it sounded like it was coming from the transfer case. Suggested I take it to BMW$$ dealer. There are no lights on the dash though. Well, I take that back, TPS needs cleaning, so check engine light is on. I'm curious if the clicking can be the gear in the actuator if there are no 4wd lights, ABS lights on?? I dont mind changing it if I need to, but not sure. Also, do I need to remove the heat shield to get to it? Thank you very much!!