When I hit a bump in my jeep going real slow I can hear a clunking somewhere underneath.. i need a new u joint on my rear drive shaft and was wondering if this is what it is?

 

What have you done so far to isolate the sound? We can only guess with the info you have given. Sounds like if the u-joint is bad replace it and see if that fixes it.
Just my opinion...
Mike

I had a loose rear shock that made a thumping sound. Do you have a thumping sound? A metallic sound? What kind of sound and where is it from? Have you gone under there and seen if anything is loose? Like the exhaust system? Are the bumpers on the rear tailgate shot so it's thumping?

 

well when i have the jeep in park and move it back in forth... you can see the driveshaft moving and hear it make a kind of clicking sound

 

That's different than hitting a bump though. Is that why you think the u-joint is bad?
Mike

 

i can get under the jeep and move the driveshaft with my hand.. also the sound is makes when i move it back and forth sounds like the noise i get when i hit a bump

 

Sounds like you answered your own question... Off to the parts store for u-joints tomorrow huh?
Mike

 

yup, get that u-joint changed....if you can slide it sideways back and fourth on top off twisting it back and fourth, get a new one ASAP...its ready to fall out