knocking noise from rear end when taking off in 1st gear

[pghpenna]

1072299

I replaced the 2 u-joints on the rear drive shaft and reassenbled exactly the same way to ensure proper drive shaft balance, I used new straps and bolts and inspected the drive shaft and all looked fine to me. After re-assembly I still was getting the knocking noise so I rotated the shaft 180 degrees thinking it may have been incorrectly installed when I had the trans rebuilt, This only made the noise worse. The jeep is a 93yj 6 cylinder 5 speed manual trans. I'm out of ideas can anyone offer any advice? Thanks, Frank[addsig]

 

[84_CJ7]

1072321

And this only happens in first gear?

Scott[addsig]

 

[Snitty]

1072327

i had a similar experience... i ended up finding that 1/4 of my pinion gear was gone, and missing one tooth on the ring[addsig]

 

[pghpenna]

1072328

Scott, Yes, it only happens in first gear and not all of the time.[addsig]

 

[jay79cj7]

1072516

I just had something similar on my CJ7... It turned out that the rear spring hanger where the shackle attaches was broken. Half the loop was gone so I just had a hook. The shackle was free to float around and give a knock against what was left, but I only noticed anything wrong when I was accelerating from a stop. Obviously I haven't been off-road lately.[addsig]