My '94 has 133000 miles on it. I can't feel anything loose when trying to move it by hand. Someone told me it might have to be dropped to see if there is a problem.

Say when going up a hill and the accelerator is backed off, it makes clanging noise when the slack it out. Sometimes it is hard to hear, sometimes not. I think it does it going downhill but can't remember for sure.

Is that a u-joint? Thank you.

 

Possibly U-Joints but most likely it is the rear pinion bearing. Lift up the axle and spin and shake and push and pull everything to see what gives.

 

Is this something that needs to be repaired right away? It doesn't do it a lot.