2555 HST Cab Transmission Issue

[GristMiller]

I purchased a 2555 HST Cab in December 2018 with 8 hours on it. At around 40 hours I was moving about 40 bales of hay over the course of about 2-3 hours. Towards the end of that time the tractor began to hesitate moving when the pedals were depressed (forward and backward). The engine RPM's did not change. Once the pedal was pressed for about 5-10 seconds the tractor would begin moving slower than normal in that direction; never reaching its full speed. If I turned the tractor off and came back after a couple of hours the problem went away. I was told that it may be contaminates in the fluid, but after I did my 50-hour service the problem has persisted. While doing my service I did see a few drops of fluid where the engine attaches to the transmission but have not seen any significant oil spots on my driveway. Again only after working the tractor hard (either a couple of hours work or a heavy task like grading) does the problem come about. I thought I had read in a previous thread of someone having a similar problem, but they never posted what the solution was. I also can't seem to find it again. I also have grown frustrated with the poor quality of the operator/service manuals (which I have seen others express the same concern) that don't seem to provide consistent information.

If someone has had a similar experience with this model and fixed it please let me know. Thank you in advance.