I have a 1988 chevy 1/2 ton reg cab short box with a 350. my problem is that when i put it in gear the engine has to labor to get it to move. i also hear a schreeking sound when im driving it slow could this be the rear drum brakes locking up or not realesing? i am at a total loss right now and dont know what to do to get this truck to run and drive like it did before. any help is appreciated thanks

used Chevrolet

 

I would jack up the back and see if the rear wheels can be spun by hand - Obviously put the truck in neutral. Also jack up the front and do the same thing - It could be a stuck caliper, but more than likely you would get a strange smell if either the front or back were locking up.
Check your trans fluid, if it is low it can cause slippage trying to take off.