C60S Transmission Question

[Phil Waterman]

I have notice a new vibration or catch in the transmission on my C60 (which I just installed a new engine). The problem only occurs during deceleration in 3rd gear on steep hills. It takes the form of a intermittent catch felt through the gear shift lever. As anybody else noticed a similar occurrence, if so did you discover a cause.

When I had the transmission out I did disassemble it to check for wear (it has been 18 years since the truck was restored) there was no metal chips in the case I strained the gear oil and ran it through fine filter with strong magnet to see if there was an unusual amount of metal particles which there were not. The only part showing wear was the pilot bearing area of the main shaft. I'm wondering if it is just bearing chatter on the pilot bearing. See picture.

I sort of expect the response - of course that is the problem, I'm already looking for new main shaft and bearing, but I looking for input so I can fix it once.