The tow valve was not the problem, since it was not touched. At first we thought it was the parking brake since it is so hard to disengage. The tractor had very little forward or reverse power, but after ensuring that it was not the parking brake, we called PT and went through a series of "try this, then this." We checked the oil level, and the oil to see if there were foam or bubbles in the hydraulic oil. We disconnected the hoses to the treadle to see if they were plugged; they were not. We changed the filter, and that didn't change any thing. Terry at PT concluded that it had to be a bad tram pump and sent a new one, which he said would take about 20 minutes to exchange. Oh, no. There are 11 hoses connected to the pump and because of the tight working space each one took about 20 minutes to remove, mark and cap to prevent oil spillage and dirt getting in. To remove the pump requires the removal of the PTO pump. Both pumps have splines that require that the pumps be slid straight forward about an inch and a half, but there is less clearance than needed, so disassembly was extremely difficult. The pump PT sent had a different transition plate to connect to the PTO. Another call to Terry, and I was infromed to swap the plates-- resulting in the exposure of the concentric gears in the pump (which I hope does not cause problems, but I kept them clean and was able to reassemble it.) The hose ports on the new pump were arranged entirely differently from the old. The suction port on the new was on the opposite side from the old. Another call to Terry, he said that the hoses have to be in the exact configuration as the original pump, and I needed to remove the factory seal from the port on the right and seal the port on the left. Having broken all possible tools trying to remove this plug, I'll take it to a machine shop tomorrow to see if they can do it. That's where I am. I'm rearranging the other ports to match the old pump. The hose diagrams in their book are worthless because they show only five hose connections (plus the treadle control hoses) whereas the tractor has nine hoses (plus the treadle hoses). Even after I get the hose connections figured out, I'm concerned about putting the pumps back in, because of the lack of clearance-- it will be difficult to align the splines and have room to manever the parts together. If I had known how difficult replacing the pump would be, I would have placed the tractor under an engine hoist and lifted the motor and pumps up to work on it -- which I may still have to do to reassemble. It is extremely labor intensive to do any work on the machine, and the lack of written instructions is just appalling. Because the pumps are different, I'm very concerned that I or anyone I hire will make a fatal mistake that'll cause permanent damage to the tractor and I'll end up with a pile of junk steel that I just paid over $20,000 for. Any advice will be much appreciated.