C60S Transmission Question

[A. Hudson]

I had no sooner finished reading your opening sentence, when I was pretty sure what was going on. A very good friend used to haul cement out of Marulan and Kandos in the 40's and 50's using Maple Leaf and Chev trucks. He explained to me in the 70's, when I was having the same problem with my C101 4x2. He told me that back then they used to carry a bag of spare bearings and when it got too bad, he could pull the box apart and be back on the road in 30minutes. Now I have never had any reason to doubt his words and he was a very clever man.
At the same time there was a number of 4x4's getting around carrying anything up to 5 ton of water and yet they did not seem to suffer this as the 4x2's. This got the better of me and I started observing propellor shafts and bearings under load. The universal joints on the 4x2 would always twitch when starting off. So where is this going..
I believe that when the propellor shaft exists the gearbox at an angle at the universal joint it is unable to turn with a constant velocity as the angle creates an uneven moment at the joint. The universal is attempting to straighten the rear mainshaft in the gear box, and the only thing stopping it is the pilot bearing between itself and the input shaft. Hence the wear.
On the 4x4 it is not so much of an issue as it travels in nearly a direct line to the transfer case.

[Phil Waterman]

Thought people might want to know what next step was. Well after various people confirmed my fears of a bearing chatter, see the chatter marks on the pilot shaft end. I went hunting for NEW parts and I found them at Obsolete Chevrolet Nashville, Georgia. Bit pricey $215 but not really if you think what the same parts for a modern truck would cost.

Any way then had all the parts new in the box. So now it is drop the transmission out and replace the shaft and bearings.

[Harry Moon]

I never did find a source for that cage bearing so i used a used one again. I'll make a note of that parts source in georgia. Good thread, I learned a lot.

[Grant Bowker]

Assuming that you are talking about the long thin, one - I found it easily at a local bearing supplier, current production.
I have also done business with www.obschevy.com or Tim Tygart's obsolete Chevy - your choice of names for them. Look specially at their NOS parts section. You have to search on part number, not a problem if you have the parts book. For example, they were able to source the early rubber covered gas pedal for the cab 13 (shared with some civil pattern) for me.

[Phil Waterman]

Hi Harry and Grant

Yes, I've used both parts sources before with good success. Obviously with NOS parts their stock fluctuates. I even found a NOS 4x4 engine oil pan for the 261 Chev engine that went into my `42 C60S, a part that I had been looking almost a year for and one day they had it.

The bearings are available relatively easily the main point of this exercise was getting a new main shaft. On the old shaft given the chatter marks where the cage bearing runs I was not hopeful of regrinding and finding a different bearing to fit. Even considered smoothing the shaft and re-machining to fit a speede sleeve.

Now I have to decide do I pull the transmission or see if I can pull the shaft in the truck. Either way it is going to wait until after November 11th veterans day event. Want to get another couple hundred miles on the truck to see if I've got to do anything else since the engine swap.

Cheers Phil