rear axle

[opelgtmaster3]

i was driving about 80 mph an all of a sudden im leaning forward, and i look at my speedometer and im doing 65mph. i get to about 75 mph and this noise started it sounded like metal was rubbing on metal. so i jack up the car and started it and i put it in gear. and let the tires spin and the noise sounds like its comming out of my differentail. but, when im in the car it sounds like its comming from the tranny. so did i blow out the rear end or did i blow out my tranny?

[GTJIM]

Always check the easiest things first:

1) Is there oil in both the g/box and diff?

2) Are the rear brakes OK or dragging?

3) What condition are the rear wheel bearings in?

While it is up an jack stands, remove the rear wheels and get the brake drums off to check the rear brakes as "sounded like metal eas rubbing on metal" tends to suggest all is not well inside there.

I always eliminate the easy ones before moving on to more disassembly. Sometimes it's the easy ones that are causing the problems.