Mysterious noise from the rear.

[dscowell]

I have an odd noise coming from the rear of my truck. The best way for me to describe it is a squeaking noise. It sounds like it comes from both the driver and passenger side. It's either one side or the other never both. I generally hear it when I'm under 23mph while under 2000rpm. It seemed to come around when I replaced my rear axle which has and LSD so I was wondering if it could be the LSD. (additive was added to the gear oil) Also the same time I put on some JKS rear shackles so I was also thinking it may be those maybe if on side is under a little more force. I'm not really sure where to start. I drove to and from Moab as well to Montana with it and nothing as acted up or gone wrong. With that I'm assuming it's nothing terribly bad but just want to make sure.

[Jim]

You comment on the sequence where it is present: under 23mph and under 2000rpm

Does it remain if you push in the clutch (man) / shift to neutral (auto) to disconnect the motor from the drivetrain?

Does it change if you're under power/coasting/decelerating?

Trying to figure out if it's motor vibration or driveline vibration or chassis vibration related.

[The StRanger]

Almost sounds like a binding U joint

[Java]

Lube the shackles?

[Spieg]

Paul previously posted:

[jayson44]

I'm with Sam: u-joint. if the squeaking increases in speed until your certain speed then disappears, I'd say a u-joint is going out. that's what mind did before it got bad enough to start vibrating.

J.

[flashboiler]

Does the noise change when you apply the brakes?

[tonkatoy]

sounds like a ujoint going bad

[Java]

I'd defer to Sam's judgement, he's a pro. I only say shackles because it's in the OP.

[dscowell]

Jim previously posted:

[Rick]

dscowell previously posted:

[dscowell]

What U-joints should I get? 1330? 1310? Something else?

[Robert B]

well considering those are the size numbers id say match the ones you have .....

[Brian]

You "probably" have 1310's.