My '85 735i starts to squeek when i put it in Drive. when it idles it sounds normal, but once i put it in drive, and it is stoped it starts to sqeek from underneeth. Once i start moving it sqeeks more and more until i hit like 10 - 15 mph then it stops, and right before it shifts it sqeeks again then goes away while in the short process of shifting and then returns for a second then goes away once more... in higher speed it doesnt make noise at all. it makes noise as its down shifting though... rpm related?

note: im forced to revv my car to about 3000 rpm when i start it to get the alternator to its propper voltage output.. ive been doing this for about a year now. and i know that the transmission fails at that rpm when in neutral or park... anything i can do or is it a transmission job?