The Stovebolt Site Forums The Shop Area Driveline Clicking noise from the rear end

I have lost the original post for this. But I thought an update was in order. Some time ago I had a click, click noise that was road speed related. Got home OK but was a bit worried. 52 1/2 ton but after pulling the drums, I have Huck brakes. Only on the rear. The front is Bendix. After 60 years not much can surprise with these old trucks. So I found a bad seal, soaked brake shoes and a weepy wheel cylinder. Cleaned it all up. Pulled the axles and replaced the seal. Shoes were about 20 dollars and a kit was 6 dollars. The parts were at the local NAPA and I was on my way. All went well and at the end of the day I was feeling good. Test drive took the smile away. Brakes worked fine. The click, click was still there. Some snow and some cold and it has been weeks. It got warm and I put it up on jack stands. Put a jack under the tube and pulled the bell from the trans to expose the U-joint. With the tube supported and a buddy turning a back wheel I found the noise. Something in the trans is clunking rather well. So we found a donor trans and will try to clean it up and swap it out. The noise is at the final output and I suspect a bearing has let go. I would expect lots of metal in the gear box so it has to be pulled and disassembled. Not fun, but it will be less work and money that ripping the torque tube out and rebuilding that part. I will let you know what I find.

Weird that you've got Huck brakes on the rear. I was under the impression that GMC and Chevy went to Bendix in '51. Did a '51 GMC brake rebuild and they were all Bendix. Odd. Did your rear maybe get swapped at some point?

The most likely culprit is the universal joint. Check it out thoroughly before going to the effort of a transmission swap. It's under the ball-shaped housing at the back end of the transmission. One word of warning- - - -before removing the ball housing retainer at the front of the torque tube, support the rear of the truck with jack stands under the frame rails, not the axle tubes! Weight on the springs will cause the torque tube to slam down as you unbolt the universal joint otherwise. It's also a good idea to support the front of the torque tube with a jack as you disassemble the U-joint, just in case.
Jerry

How many "repairs" in 60 years? Who knows. The U- joint and bushing in the tube are new. I checked with the truck on jack stands under the axle. And a floor jack under the tube. Pulled the bell back. transmission fluid drained from the bell. About a cup. The U-joint was still snug in it's home all bolts and clamps looked good. When one rear wheel was turned by hand the U-joint was smooth and tight. The transmission was making the click/clunk noise. Only thought I have...when the bushing was replaced in the torque tube it was tight. The U-joint slip onto the drive shaft was tight. I may have put some pressure on the yoke in the transmission that has caused the output shaft bearing to fail. The process of putting the U-joint back together was tough with almost no clearance between the drive shaft and the transmission. I lifted the transmission to get the room I need to get the U=joint back together. Was as if the drive line was too long. After the U-joint was in place I lowered both the tube and transmission until the rear mounts were supporting the engine and transmission. Then I pushed the U-joint fully into the yoke and secured it. Might have been a 1/4 inch. I never gave it a moment of thought.I would bet it has to move on the drive shaft more than that. So now I get to pull it apart and fix the bearing and whatever else the metal from it has done. Good news is I have a donor transmission that is in good shape. I have come to suspect the truck is a "bitsa" truck. A little bit of this truck, and a little bit of that one over there. Hense the early axle on the back, the later one on the front. And a 235 to go. All in 1 1952 1/2 ton. Oh there is an alternator and a 12 volt regulator on it as well. But, a 6 volt starter...go figure.

My clunking noise in my 35 standard turned out to be 3 teeth broken off my ring gear.