Runs good with no problems but then when everything gets hot after an hour or so then when you are into a load it won't break loose. You can keep pushing the levers forward and there's no drive power and the tires won't break loose almost like the hydraulics bypass. If you play around with the bucket functions up/down and tilting you can regain the power and the tires will then begin to dig In and spin. The pump is completely rebuilt with rotating groups,orings,swashplate,etc. And drive motors are new as well.
Did this issue happen before or after the pump rebuild? I would check your charge pressure when hot. It should be 390-410psi. The charge relief is shim adjusted. 0.020" shim will increase 12psi.
It was doing it before the pump rebuild but it was really bad and you couldn't get it to regain power no matter what. Then they rebuilt it and it was the same way so I ordered a new chargeneration relief and popet and it wouldn't do it until it got hot and like I said it would regain power with messing with bucket functions. Someone mentioned that it gets 5psi from the manifold relief block in the rear of the machine and I'm not sure if that sounds like that would fix my issue. I can't find anywhere to just purchase a relief for that without purchasing the whole block for $400ish. Alot of money for not knowing if that's the issue.
That's a bummer of a problem to isolate. After you mess with the bucket functions and it comes back to normal, does it continue to operate normally for a long time, or will it revert into the no-power mode again pretty quickly?
Comes right back to no power if you let out of it and go back in. It will stay digging in as long as u don't let off
Since the engine never bogs down what are all the possibilities? Someone on another forum mentioned tow valves and I know there are 4 relief valves left/right forward and left/right reverse but I can't imagine all 4 would be bad (unless 1 would effect all) since this problem occurs in forward and reverse and I already changed the charge relief and poppet. Then there is also a bypass valve on the charge pump. Then the only other thing but it is not part of the pump is that waterford/sterling relief block manifold that I am told gives the pump 5psi and it has a relief valve??????
Did you ever get this fixed? My 75XT is doing the same thing.
It was one of the pumps on the hydrostacic tandem drive. There are 4 5/8 serice ports on the top of the charge pump and they should be about 4500 psi and one side was about 400 psi so I capped off the hydraulic lines on that side and to eliminate the drive motors then swapped relief valves to eliminate that and no change so now I need to rebuild the pump