JD 2025R won't move after input shaft replacement

Jackstand · Sep 26, 2019

2014 JD 2025R. with 260 hours. Driveshaft u-joints went bad, driveshaft broke and snapped the input shaft at the same time. Removed hydraulic pump assy, disassembled, replaced input shaft. Now it's all back together. The three-point and the PTO work properly.
Everything seems normal until the traction pedal is pushed, either forward or reverse. When I do that, the pump gets very loud and the engine strains. The pedal pushes back on my foot. I can stall the engine if I push hard enough on the pedal. There is no sensation of power reaching the wheels at all- it's as if the pump is working properly, the pressure that is created is just being dead-headed instead of being allowed to push on the wheels. This happens with the gear selector in any position including neutral. In neutral, I can roll the machine forward and backward as expected.
I don't have a manual, I am only using the parts explosion at John Deere's web site. (As a first-time poster, I can't put the URL here).
Any ideas before I take this thing back apart? I don't mind doing that, it's just that it felt right when I put it together the first time. I want to make sure I test everything possible first.
About me- I have no previous experience inside a tractor transmission. I am a 30-year auto mechanic with a lot of (mostly MOPAR) automatic transmission experience, though.
Thanks in advance for any suggestions.

Maryland

RNeumann · Sep 26, 2019

The only time I get that sensation is when I have the parking brake on or I’m in too high of gear. Obviously it took some doing to grenade u joints and do the damage you did. I’d start by getting the tires off the ground and seeing what is happening with no load on the drivetrain. Then I’d try to spin the tires with the machine in gear but not running. I’m guessing something in the drivetrain is binding- it may be what broke the u joints.

Jackstand · Sep 26, 2019

Thanks RNeumann.
This tractor is owned by the Parks Department, so maintenance is uneven and operators even more so. The u-joints had never been lubed (poor access/ design by JD here shares some blame), and the seasonal employee wouldn't have stopped operating the tractor unless it vibrated enough to throw him off. My point being, I am leaning toward no internal failure caused the problem.
I did follow your recommendation- wheels move fine when off the ground (differential lock doesn't engage though- ?). And problem remains when axle is raised.
So it must be something I did. Is there any pressure port I can check before I take it apart again? I am afraid of taking it all apart and finding no problem. If the problem is in the gear transmission behind the pump, I won't mess with it, but I want confidence that the problem is there before sending the tractor out.