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.

Steve H