Whining Transmission

[EricChanning]

As of recently, my Turbo 400 AT started whining. It has a large oil cooler and about 4,000 miles on it since I had it rebuilt. It is a RPM whine, not a speed whine. The fluid was a little overfilled, so I drained it but that didn't help (6 ozs). The oil seems very clean. The Vehicle is a 304 cui '73 Commando with 86K original miles. I added Slick 50 AT conditioner last night and it didn't help either. It shifts and runs great. I doesn't seem to whine in reverse, or barely in park but it does in neutral and most apparent when the RPMs are higher in the Drive. Anybody have any suggestions?

[rstarch345]

I can't speak for your trans specifically, but when I rebuilt the trans in my M151, I put in all new gears. About 5-600 miles later it started whining and finally leveled off. I attributed it to gear wear in. It's a similar issue with differential gears. They seem to develop a whine and one just has to live with them.

Although, in all M151s the diff gears are so loud you need ear plugs.

That's about all I can offer.

[Military_Man]

Its the gear ratio its to low mine does the same thing 250000+ miles on it.