I'm having some issues with my 1989 535I. The transmission started slipping today, It goes up to 4k rpm before it engages and is doing the same thing basically in all gears if I hit the gas hard , the tranny slips. I'm not sure if it has anything to do with me getting stuck in the snow this weekend , and I just kept switching gears from reverse to Drive to get it unstuck, Is there anything I could do to fix this issue or should I just start looking for a new tranny.