Rear end Bouncing

[billrobbobjo]

I got this 1969 GMC truck and i was looking on here and couldnt find any problems quite the same as mine. Its a 3/4 ton, and i attempted to get home from college one day, and i was going down the road and i heard a loud pop and then the rear end of the truck started bouncing, at about 45 miles an hour. I turned around and went back. I blew out my hanger bearing after working on the drive shaft for about 24+ hours, Aka rust and stuff. I dont really dare to go over 40 again due to the chance of it happening again because when i get up to about 40 the motor seems to sudder for a few turns which seems like a carb problem and the rear end of the truck starts to bounce. Its not a smile bounce its like one i had to stop completely before it would stop. Any advice, Should i replace the rear leafs or what? Just looking for some Advice!
Thanks Robert