I thinking of buying another 98 xk8 after driving for 20 minutes it start slipping. Would that be in the transmision it self or could it be the transmission module? Any help on this subject before I make a decision on should buying it or not.thanks Kevin

 

Run don't walk, RUN away from that car. Cheap entry price with these typically equals to much more money to get it to a good place mechanically.

 

It's the transmission. It may be just low on fluid, but no matter what the cause, you either need a lot of experience to evaluate a jag, or hire an expert for a PPI. A couple of hundred dollars upfront can save thousands.