95 E320 wagon buzzing sound (transmission?)
Hi folks! Wondering if anyone has any ideas on the following:
About two seconds after startup in the morning (only when cold) there develops a relatively loud (louder than the engine) buzzing sound from somewhere near the tranny pan that persists for nearly forty seconds, all the while lessening in volume until it reaches a steady state volume which is very quiet. Same thing no matter whether the car is in park or in gear and moving. The car has 60k miles and has not had tranny service for almost 5 years (at 30k). I just bought the car this year. There is some slight harshness with the shifts, but I have driven GM all my life and am used to butter-smooth shifts so it's probably shifting normally. I will be doing the fluid (Mobil 1) and filter sometime in the next few weeks. Just wondering if anyone knows of some simple problem that may cause this condition, which I could address while the pan is off. Did several searches and found nothing. Is it even the tranny?
Thanks very much.
1995 E320 wagon