Rear U-Joint

[dscowell]

Here are the U-joints

This one should be the one at the axle



Here is the one at the t-case. It is missing the grease zerk because it broke off while I was replacing it. The zerk worked fine before I replaced it.




This is one of the cups. Its not the best picture but all of the needle bearing from all of the cups were straight but they were not all the same length... is the normal wear?


Sorry for the pictures being so big.

[Hypoid]

dscowell previously posted:

[dieseldoc]

Can you clean them off, need to see the cross clean to know if you having any bind that is creating any Birneling.

They have good grease in them.
The cups don't seem to show any heat build up.

Before you pulled them out did you spin the cups and move the cross for the side still in the drive shaft???

Am looking for any binging.

For the drive shaft side, measure the ears outer most point and then inner most point of the hole.
If there is any difference this will cause bind and thus your issues.

The joints seem in good shape,

Back to the slip yoke, do you have at least 1" of travel from the yoke.

My TJ drive shaft was binding and not sliding. This caused issues.
Kind you your drive what is far longer and has better angles on it than my TJ
But if the slip is not doing it's job your u-joint will take the beating.

[dieseldoc]

Hypoid previously posted:

[Spieg]

dscowell previously posted:

[dieseldoc]

X2 on this as well.
Should be the same length and thickness.

[dscowell]

dieseldoc previously posted:

[dscowell]

Spieg previously posted:

[dieseldoc]

The discolor and marking is showing a lot of wear.
Looks like the chrome is worn off and starting to have Birneling.
The groves are from the needles not moving.
I am willing to bet the drive shaft has come out at some point and is no longer parallel.
One of the ears on the shaft yoke is twisted.
This you are getting bind and no amount of lube will keep this from happening again.

Get the calipers out and measure the ears in at least 4 places the measurements should be the same.
I bet one of the ears is twisted.

[dscowell]

Last year around this time I was having the same problem and couldn't figure out what the problem was and the joint by the axle blew up on me. When it blew up it took a good chuck out of the ear on that end but it was still intact to still use. But the joint that blew up was still squeaking before that happened. I never had this problem til the new axle was in place. It shouldn't be the driveshaft unless it's the length because it was not a problem before this happened last year it has to be the axle or something related.

[dieseldoc]

Hmmm....sounds like time to hunt down a drive shaft.
Or have the rear ear replaced.

[dscowell]

alright...

So I guess my last question is why did I only hear the U-joint between 2500-3000 rpm?

[redneck23ms]

U-joints shouldn't make noise based on rpm. Only speed. Maybe it's not the u-joints that you are hearing.

[Jim]

dscowell previously posted:

[dscowell]

Jim previously posted:

[Jim]

Can you sit in neutral, stopped / not rolling, rev the motor to the desired RPM and reproduce the noise?

If yes, I'd be looking at something motor related (front of motor accessory belt bearing perhaps)

[dscowell]

If the truck is not moving there is no noise. Once the joints were replaced the noise is no longer there that's why I assumed they were the cause of the noise.

[dieseldoc]

hmmm......I think u-joint was going out yes.
but the noise being only at said rpm
that a u-joint for ya.
had some front shaft joint that would only cause issues if I hit a bump at a very specific speed.
other wise smooth and quite

I think you still have an underlying issue.

[dscowell]

Okay so lets say you guys are right and the joint is not the primary cause of the noise... where should I start my search for the problem?

[dieseldoc]

Rear diff.
As the u-joint was the axle side joint that's where you should start.

I still am not sure what is causing the damage you have.