I recently picked up this 70xt for little to nothing because it didn't move and the company didn't want to spend the money to fix it. I got it to move by replacing a relay and I thought I got lucky. Turns out it moves until you start working it. I was cutting some sod off today and it would dig until it got tough. Levers all the way forward and it wouldn't move or spin. Back up and try it again and it would do the same thing. There aren't any light on and I replaced the filter when I got the machine. There must be a pump issue like was stated. Can I buy a rebuild kit for the pump or do I have to just buy a reman pump?
Before you just condemn a pump, you should do a few checks first. When you are under load, try just moving one side, and see if it has better power than the other. The drive motors on the xt series were problematic. Usually when the drive motors are weak, they will fill up the chain case. So check your chain drive levels, if they are way over full then you probably have a weak/bad drive motor. Also check your charge pressure. Check it at an idle, and also check it under load.
I checked the chain case levels a few weeks ago and they are fine. I did talk to a mechanic at our local dealer and he had me do some tests to possibly trouble shoot what's wrong. He had me unhook one drive motor off the pump at a time and cap the pump fittings and then start it and slowly push the lever forward for that drive to see if it puts load on the engine. The right side just about choked the engine off, which is what he said it should do and the left side made the engine labor slightly compared to the right side. I also capped the lines from the drive motors to see if I could spin the tires. He said if the pump is worn out the tires will spin. They wouldn't spin unless I loosen the caps to let oil come out. I would say the front pump needs work and must be leaking oil by between the two pumps.
The 2 piston pumps share charge pressure, so yes, if one piston pump is bad, it affects both. Your testing isn't entirely accurate, but should point you in the right direction. By the time you can spin the wheels with the motor lines capped, the motors are completely failed. I would agree that your left side is the weak point. I would recommend getting the left motor rebuilt, as well as the pump. If you see any brass in the hoses, you should change the hoses too. (the brass gets caught in the rubber of the line, and then comes out later into your new or rebuilt pump) The more accurate way to test is to measure charge pressure, and the charge pressure drop when the pump is under load.
GARY, What do you think is going on if you find pieces of metal screen in your hydraulic filter on a case machine. The lift seems to be getting weak. If the tandem pumps are needing a rebuild what else needs to be replaced and what is the typical cost of a rebuild.
Loader lift, bucket and aux gets its hydraulic power from a separate aux pump attached to the front on the engine, the hydrostatic drive pumps are coupled to the rear, the drive pumps "hydrostatic" have no affect on the loader,bucket and aux pump since they are separate from each other and only share the hydraulic oil from the res , if replacing the loader pump you will also want to replace the spline coupler which attaches it to the front crankshaft pulley price for a reman aux is about $550 and coupler is about $80 also if the serpentine belt shows any signs of wear do it then since you have to remove the aux pump to replace the belt. Depending on the type of metal will show what is failing Brass tends to be drive pumps, Aluminum is charge pump , Steel tends to be aux pump or possibly drive motor on your model, also size of the metal is sometimes more important. Finding a tiny amount of small flakes is better then finding large chunks. unless its brass or aluminum." drive pump or drive charge pump"