JD 4200 hydrostatic 2002 2 wheel drive

I have a 2002 JD 4200 hydrostatic , rear wheel drive and it has three speed ranges, A, B and C. Yesterday I was driving down the road in the High
range (C) and the tractor came to an immediate stop just like when you suddenly take your foot completely off the forward pedal. When I pushed the
pedal back down, it would stall and I would restart the tractor. I was able to restart the tractor and drove it home in low gear (A), but when it was
in B or C range, it would stall but it was very difficult to shift between the ranges. When I got it home, I shut the tractor off and then could
shift it between A, B and C, but it was difficult to find neutral. I was able to drive the tractor again around the yard, but it would only operate
at very low speed without stalling in B or C range. In low range (A), it is fine. Now I have it back in the garage and have it is in low range (A)
but it will not shift to B or C, the gear selector is locked up in the low range. A few months ago, I put brand new fluid in the tractor.... J20D low
viscosity, a new hydraulic filter, and I removed and cleaned the suction screen. The fluid at that time looked like it was old but there was only
very minimal material/filings in the suction screen. The loader and the three point on back are working fine. Any ideas of what is going on here????
Thanks for any help.

Is there a port , plug or cover that will allow a visual inspection ? Sweepingva magnet along the sump bottom will find metal filings .
Could be a bearing going or a shaft galled.
Should not have driven an inch farther after the difficulty started . Just makes the damage worse and the cost to repair higher .

There is not, it is all sealed up with now visual inspection ports. I could remove the sump screen again, but will have to drain the 7 gallons of
hydraulic fluid to do so.

the range shifter forks and shafts were famous for breaking on those, I have a PDF of the tech manual that you are welcome to, if wanted, shoot me your email

Joe

There is an updated range selector handle etc hoping I don't have that problem with mine. But it is stiff shifting between the ranges.

Joe. I would really appreciate that. Can you send it to [email protected]

Thanks

Mark

sent just now

I don't know the answer....but PLEASE let us know what you discover to be the fix. Thanks in advance.