Newbie here-looking for some answers for a Takeuchi TL26 issue

as stated I am new here,been lurking around for about a year-discovered a wealth of info-I have used the search function and have found people that have had similar problems but there have never been any definitive results posted for the "fix" of the issue.Here is whats going on:94 TL26 new motor-runs great-New left side final drive-works great-however the right side seems to be weak and it is causing it to track to the right,not a huge issue but annoying none the less.The real issue is after it runs for a pretty long time and the hydro fluid gets good and warm it seems to loose some of the forward/reverse drive power-Now the odd thing is that if I shut the machine down and restart it within 10 seconds it will work fine for another length of time,I know that the controls are all hydro and there are no electronics(according to my local dealer)but it seems like when i shut it off it may be releasing a stuck solenoid or something.This is my first skid steer and I am a mechanic by trade but I am very unfamiliar with this machine and how the hydro system functions-The dealer also told me there are servos on it but they felt that wasnt the issue and told me to use it until it fails,not the best advice... It should be know the first thing I did to the machine when I bought it was to not only change but flush all the fluids and replace all the filters-even went so far as to cut apart the hydro filter and inspect it,to my surprise there was zero evidence of metal in the filter..any help would be appreciated,also I need a parts and service manual if someone has a set they would like to part with-thanks in advance