Reverse noise

aeo

Well-known member
Had the u joints replaced, now the truck is running well. Except in reverse. Doesn't matter if it's in gear or not, consistent clunk when going backwards. I can hear it and feel it.

Where should I start looking?
 

SARTech

Well-known member
Nothing else was done, just replaced the U-joints?
Do you mean, if it was in neutral and rolling backwards you still have a clunk?
 

aeo

Well-known member
Nothing else was done, just replaced the U-joints?
Do you mean, if it was in neutral and rolling backwards you still have a clunk?

Yes and yes. The bolts were replaced on the drive shaft as the original ones weren't the correct size/length.

"Constant clunk" meaning.... repeating clunk, clunk, clunk....?

Consistant, like every rotation at the same spot it clunks. Hear it and feel it. Only going backwards.
 

SARTech

Well-known member
I can't really say what it is. Its strange that its only making noise in reverse. If you put the truck on jacks and crawl underneath and rotate the axels backwards it might be easy to pinpoint.
Since it didn't do it before the u-joints were replace, the logical answer is its one of the u-joints causing the noise.
Also could be the driveline is out of phase.
Let us know when you figure it out.
 

Viton

Well-known member
The front shaft has a certain phase which can be lost IF you pulled the yoke slip joint apart. Since the front has a steeper angle than the rear, those U joints are usually 1st to fail. Be sure to lube them every 5,000 or less.

Check the LR service manual to get the correct phase of the U joints, I think it supposed to be 90 degrees off from the fixed end yoke U joint, but I'm not 100% positive. It's always prudent to mark the slip joint & main shaft in case you happen to pull them apart.
 
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