I have a International 2500B with frontend loader and backhoe. The transmission is a hydrostat and it will not move now. When I first bought it it would move in reverse after I changed fluid and all filters. Was told charge pump maybe bad, so I split the tractor and found that charge pump internal components had been remove. Bought Used/new charge pump and now it will not move at all. Any suggestions? Also, I have been told that the International 574 tractor are basically the same tractor as the 2500. Question is if I found a 574 tractor with a manual transmission would the hydraulics operate the backhoe and loader properly?