On my drive up to Estes Park for the weekend, I noticed a drivetrain vibration getting worse. The mechanic who serviced the transmission a few months ago mentioned a bad ujoint. That's the understatement of the year.
I pulled the driveshaft and discovered the upper ujoint was flopping around loose. So I removed it and disassembled the end caps.
Instead of finding steel roller bearings and grease, the only thing in one of the caps was coal-black dust and rust. The roller bearings were long gone.
Which explains why the bearing surfaces were severely heat damaged, rusted, and pitted. And why there was a ton of play in the joint resulting in crazy vibration.
The seal had cracked wide open which probably let the grease out and let moisture in, destroying everything. The lower ujoint was ok, but the grease was obviously way too old.
Major shame on me for neglecting to lube the chassis over the last few years. Ugh.
I swapped in a spare driveshaft after installing brand new, heavy duty, greasable ujoints on both ends and lubing the shaft. The vibration is gone; I didn't realize how bad it had gotten.
Time to lube everything else, repack the front wheel bearings, replace axle and transfer case fluids, and perform a bunch of other preventative maintenance...