A few days ago, I removed the driveshaft on my 100% stock 1960 Ford F-100 to restore the driveshaft and replace the u-joints. The vehicle never made any wierd noises or vibrations, and the u-joints still had plenty of life left on them. I simply wanted to restore the driveshaft. Today, I re-installed the driveshaft with fresh paint, and two new forged steel Brute Force u-joints. I cleaned the rear differential yoke up, lubricated the mounting pads with a little synthetic water-proof chassis grease, and torqued the rear u-joint straps to 15 ft/lbs. On the first test drive, I made it down the road a little ways when the driveshaft started making this really fast squeeking sound (like when you rub a old dry-erase marker on something slick really fast). The sound will sometimes go away after making a turn or at around 10 mph. It sort of seems like it comes and goes when it pleases, regardless of the road condition. I brought the truck back, and the two ends of the u-joint which sit in the differential yoke were so hot I almost burned my fingers on them, however the rest of the differential was not even warm. The other two u-joint caps were warm, but not near as hot, and the same with the front u-joint caps. The whole back of the driveshaft and the differential yoke were quite warm as well. I removed the two u-joint caps (the ones which mount to the rear differential yoke), and the once all-white lithium grease in the caps was now grey. I put a little synthetic grease in the cap and re-installed them, torqued the caps, and went for another test drive, same thing, however this time it took a few more minutes until it started with the noise. I've worked on all sorts of cars over the years, but have never had anything like this happen. These are also solid u-joints without zerk fittings. Does anyone out there have any ideas what might be happening? Do I have the rear straps over/under torqued? Is the u-joint itself defected? Any ideas and help would be greatly appreciated.

 

TA

Tough without seeing them. If you didn't get a needle bearing out of place, check for smooth operation off the truck. New joints may be a little snug, but they should rotate in all directions freely with no grabbing. I can't say I have ever purchased a defective u-joint, but it's possible I guess. Are they identical (where it matters) to the ones you removed?

 

The u-joints are different than the ones removed. The ones removed were greasable (not as strong) and the rear one had a cap retainer strap (probably the original as the truck only has 120,000 miles). The new u-joints fit in perfectly, are forged, and are much stronger. Like I said, the only arear giving me trouble are the two u-joint caps which mount in the differential yoke. The Dana/Spicer site states the oxidation in the grease may be from improper u-bolt torque. I had to use the torque specs from an old Mustang book to get the general idea of where they should be torqued, which stated 8-15 ft/lbs, and I used 15. Should they be torqued less or more?