Greaseless/sealed U-joints

I have seen one fail at about 750,000. It was never loose. It took out a high dollar brake valve, 2 chambers, one air bag and a tow bill. Replace them all !!!! If anyone has one with low mileage they have a plug in the middle of the joint. You have to take the straps off to get to them but can install grease fittings. Then there are the other ones. While you are at it take the plugs out of the S-cam housings and slack adjusters. Install grease fittings and grease them also.

 

The sealed joints are the way to go. The greasable actually don't last as long generally. It supposedly has to do with the end caps having a better seal to keep abrasives out.

Anyway, 750k is all i would go and just change them out. Better safe than sorry.

 

I have one failed at 780.000 ( front drive axle input) . Rest of them failed at 1.2-1.4 million miles. They were Meritor RPL series u-joints.

 

All you can really do is disassemble it from the yoke and move the end caps by hand and feel for any binding and excessive play. It is also a good idea to check the slip yokes too to make sure they still slide in and out nicely. Once those seize they will send vibrations that will take out your trans and/or diffs.

 

I have conventional u joints. They get examined monthly. I find once they get some up and down play in them you are on borrowed time. That being said ive run them for 6 months or more after finding a little up and down play. Like a 1/16" once it starrs getting worse rhen they get changed. If there is axial/ twisting play then they are are changed immediately. I also watch for the caps turning in the yoke. You should be able feel the roughness in the truck when its under load when the trunnion gets pitted and starts eating up the rollers.

 

I had a 2000 century that I bought with 500k on it with sealed joints .
Replaced the first one at 550k and by 700k I had replaced them all .
Not all were bad tho just replaced them while the shaft was off .