Lately I've been noticing a highpitched whining noise coming from my tranny. It seems to occur only after I have driven for 1.5hrs+ in a single day. I don't hear anything at idle, only when I have the car accelerating in 1st, 2nd.... I can't tell if I'm getting any whine in higher gears cause my exhaust is too loud . Anyone have any ideas as to whats cause this? Also, I changed out my tranny fluid for synthetics once I bought it(about 16k miles ago). The car has 81k miles on it now.

 

Could the noise be coming from the diff? I was talking to some people today, and the only thing they could think of was to check the fluid levels.