I bought a great looking 1990 735i from a gentleman that was going to send it off to the crusher. Engine purrs like a kitten and seems to be in overall great shape. Problem is it wont shift from 1st gear when in auto mode. Put it in manual mode and it shifts just fine 1 thru 3 but will not shift to 4th gear. Any suggestions on what I should do to troubleshoot or fix this problem. Like I said she is to pretty to send to the scrap yard.