About a month ago, I filled the transmission with 90W oil and took the truck for a spin. I have a 1949 4400 with a 235/SM420 combo. While driving, the clutch started to slip and no power to the transmission. I limped her home and let her sit. I believe the clutch disk is getting oil soaked when I drive the truck. I try and drive the truck once a week. When I first start out, the truck runs great. After about 3-5 miles, the issue comes back. No power in upper gears, and limp home in 2nd or even 1st. Transmission shifts smooth, no rattles or noises. Truck only hase 18,000 miles on it, so I don't think the tranny needs a complete rebuild. Was wondering if there was any type of seal in these transmission or what might be the issue. Any help would be appreciated.
