How do I know if my U joints are going bad?

[SSalzer]

I hear a squeaking sound just after I start rolling until about 35 mph. I gets faster with road speed. Engine RPM does not affect the frequency of the squeaks. The noise also stops if I step on the clutch. I went under the truck, grabbed the drive shaft and shook it. There was a little play in it. Is this normal? I've read so much about U joints failing and was wondering if this is the beginning of the end for mine. I have just under 40k miles.

 

[TCDiesel]

Whats the Mileage. it sounds more like drive-line , or hub assembly/ies.

 

[SSalzer]

40,000 Miles. Maybe I should have stated that I was talking about the drive shaft U Joints.

 

[JFaughn]

There should be no play .
If your hearing squeaking [ dry bearings ] then you should be able to see a rust dust around the cup seals .
Unless they are real bad , you may not be able to feel slop in joints , with out dismounting the shaft , too many things putting tension on then to feel , most of the time .

 

[Cattletrkr]

... I went under the truck, grabbed the drive shaft and shook it. There was a little play in it. Is this normal?

Where is the play? Do you have a 1 or 2 piece driveshaft? The center bearing for the 2 piece will have some play, a lot more than you might think. The rubber around it allows for the play. If you have a 1 piece there shouldn't be any play. Once there is play, there usually isn't any squeaking or squealing. By then it's time for clunk clunk.

Get the rear tires off the ground and check the joints. Much easier that way.

 

[SSalzer]

F. Y. I. It was my rear drive shaft U joint that was squeaking. I replaced both with Precision 351's and the noise is gone. There was no grease at all in the one that was making noise.