'64 C60 with 292, SM420, and 15k two speed rear end. Engine and trans are freshly rebuilt. During rebuild I installed a new clutch kit with the old throw out bearing (new and old had different overall lengths). The truck seems to have a bad slipping clutch now. Noticed it a bit during the last heavy load but "clutch slip" never came up in my mind. It was a soft almost shudder after upshifting and beginning acceleration in the new gear. Most noticeable on the 1lo - 2lo shift. Two weeks ago just moving dirt around the farm, she got really bad. From stop and in 1 lo, she would just barely groan into movement regardless of RPM. Stopped next to even just a small 2" mount at the rear tires, she flat wouldn't move. Only 2-4k lbs of dirt on the bed at the time. Once dumped she would move, but slip bad. Road speed tops at ~20mph.
Before the rebuild, the trans whined. After the rebuild the 420 still whined. Never though twice about it. Now wondering if its been something else whining. She whined in reverse a lot more lately which made me start to dig but nothing found. Trans shifts fine, fluid looks good, etc etc. I am chocking up some of the wine to the brass pilot bushing which I will swap to a bearing style.
The 292 is 100% fresh and runs like a top. Cork gaskets so she seeps, but no true leak of oil to warrant adding any. There is a small amount of motor oil on the trans, but no real indication that the rear main would be bad and oil soaking the clutch. Rear main was really bad prior to rebuild and I never had oil soaking issues on the old clutch. The PTO weeps out trans gear oil, but again, not enough to warrant topping the oil off. Maybe the front main of the trans wasn't installed proper?
Research shows that the clutch fork could be at fault due to excessive wear which this truck definingly had prior to rebuild. Maybe its a combo of everything; worn fork, incorrect throw-out, flywheel needing machined, etc. Maybe I got a lemon clutch? Pulled inspection cover and nothing seems out of place or oily on the flywheel or clutch. Clutch adjustment seems well within specs. To date, I have not noticed any burning clutch smell, and no smoke from the clutch at all. That alone makes me wonder if its a problem with the rear end, but that doesn't seem logical to me. Regardless, I am prepping to drop the trans again this week for inspect closely. Any ideas on what to look for?
