Hello guys a have a international with a Cummins and Allison transmission automatic. Today I went to backup and the truck moved very slow. Then it would kick in fast Then Slow again. I was able to back it up very slow . The truck was in a lil bit of a incline but barely noticiable and I had 41k on the trailer. Don’t know if related but I can hear a boost leak. When the turbo comes on . But truck runs fine when going forward when I apply the engine break I can hear a clicking sound. also had a seal replaced on the trailer. When I stopped it felt hotter than the others. Not scorching hot.
Sounds like a clutch pack starting to pack it in.. Hydraulic Pressure controls the engagement (and the constant engagement thereafter), to me it sounds like its having a hard time setting it and forgetting it. Try a new filter and top the fluid after, and see what happens. If it doesn't fix the problem then that clutch pack probably needs a refreshing with seals/orings as well.
