Diesel fuel is cheap, it's a good solvent, and it's got enough of an oil base that it won't promote rust by getting things too clean. Pour about a gallon in, spin the trans for a few minutes with your drill motor, and let it drain overnight. Refill with 90 weight mineral oil (not hypoid lube) and drive on
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!