[emmagator]

Ok under load or up a hill my tranny sounds like it has a bearing going out, like bearings rattling. This is only under load not just cruising. What bearings should be replaced to attempt to solve problem. Thanks

 

[JoeIsuzu]

Why are you positive it's even a transmission bearing?

Jack

 

[racerx55]

Alot of transmissions make a rattle or gear chatter sound under load at certain engine RPMs from harmonics, if its a constant speed or RPM related rattle it could be a chipped tooth even from age.
Only way to see what needs replaced would be to tear down the trans and visually inspect all of the bearings for wear, replace and readust preload or endplay accordingly.
it could be anything though. usually once a trans is opened up theres more problems found than you would expect caused by others that started long ago. Post a video of the noise if you can.