clunking noise from the rear when i accelerate hard
 

hi just got a 1997 lariot with the 4.6 last weekend. my friend who i bought it from told me it needs u joints. my question is when im at a stop or going slow and put the pedal down it makes a terrible grinding/ clunking noise from the rear then goes away after a few seconds. is this the ujoints and im just paranoid? or could this be something bigger. this is my first truck and i just started school and trying to get the truck in tip top shape for commuting daily.
thanx you!
matt

Could be U-Joints, axle bearing, axle wrap, bad driveline geometry, or a kangaroo skull in the differential. Climb under there and look! Look for oil leaking out of the axle tubes. See if you can wiggle the driveshaft without turning the yokes. No way for us to help you. You need to check it out yourself or have someone check it for you.

usually if U joints are bad the drive line will move if you grap it and shake it. Check it. I'd also check the rear brakes.. and check the stuff mentioned above.

thanx guys! this is my first vehicle and i know only the basics but trying to learn as much as i can my buddy who knows the truck well is taking a look at it tommorow