I have a produce farm and a year ago I bought a hydro 656 to run a harvest aid conveyor. On the cold day when I bought it I tested the transmission with the brakes to see that it did not slip and it seemed fine. The first time I drove it up a big hill on the road I found out that the transmission was slipping. I did all the obvious stuff like changing the filters and fluid but it still slipped. I was looking online and came across a company called Herrs Machine that specialized in rebuilding IH hydros. I called them and the person I talked to had a very good understanding of the transmission in my tractor. He asked questions to understand what was going on and took the time to thoroughly answer my questions. He told me to cap off the two lines coming out of the transmission and then see if the problem was solved to rule out the possibility of the drive control valve or the foot n inch valve malfunctioning. That did not solve my problem so I bought the service manual and educated myself. I got some gauges and checked all the pressures I could. They were all fine except the forward drive which cut out at about 2500 psi. As I was testing I realized that the tractor only slipped in forward so I studied the repair manual and looked for areas that held forward drive pressure that could be leaking. First I switched the forward and reverse check valves, but that did not help. I suspected the forward drive pressure relief valve but the wording of the manual made it seem like that couldn't be the problem "high pressure relief valve stuck open will affect both sides the same way so it is impractical to switch the valves to test them", so I called Herrs Machine again and they said I should switch the two relief valves. So I did and my slipping problem moved from forward to reverse. The key was that the relief valve was not stuck open but would leak enough to not allow buildup of full drive pressure. The next morning I called them back and ordered a relief valve and new gaskets. It pays to talk to people who know what they are talking about. Herrs Machine and other friends who talked me into getting a manual and working on the hydro myself saved me thousands of dollars. Since I have a good Hydro tractor now, my next project is to paint it.
Also if anyone is reading this and thinking about getting a hydro for a vegetable farm, I would highly recommend them. It is very nice to be able to travel from barely creeping to seven mph without stopping to shift gears or the jerking caused by a powershift. Last summer my other slow tractor was a Kubota m100X with a creeper range and 8 speed powershift; aside from being in a nice cab, having four wheel drive and more power the 656 was better for the conveyer. I also tried to run the conveyer with my 4020 and that was terrible, you had to constantly have your foot on the clutch and then just let off for a second to pull up a little bit, then either take it out of gear or hold the clutch in until the pickers caught up. The conveyer works the best when it is by the pickers not if it is five feet in front of them. I bought a hydro 86 this winter to run another conveyer I built for harvesting tomatoes, so I can leave the Kubota hooked to the sprayer. I like it better then the 656 because it does not have or need glow plugs. The hydro is also easy for migrant workers to understand, the glow plugs and making sure they used the correct range were the things to watch to make sure they were driving correctly. It is also nice to put hours on the tractor that is already almost fully depreciated instead of destroying the value of my newer tractor.
Also if anyone is reading this and thinking about getting a hydro for a vegetable farm, I would highly recommend them. It is very nice to be able to travel from barely creeping to seven mph without stopping to shift gears or the jerking caused by a powershift. Last summer my other slow tractor was a Kubota m100X with a creeper range and 8 speed powershift; aside from being in a nice cab, having four wheel drive and more power the 656 was better for the conveyer. I also tried to run the conveyer with my 4020 and that was terrible, you had to constantly have your foot on the clutch and then just let off for a second to pull up a little bit, then either take it out of gear or hold the clutch in until the pickers caught up. The conveyer works the best when it is by the pickers not if it is five feet in front of them. I bought a hydro 86 this winter to run another conveyer I built for harvesting tomatoes, so I can leave the Kubota hooked to the sprayer. I like it better then the 656 because it does not have or need glow plugs. The hydro is also easy for migrant workers to understand, the glow plugs and making sure they used the correct range were the things to watch to make sure they were driving correctly. It is also nice to put hours on the tractor that is already almost fully depreciated instead of destroying the value of my newer tractor.