JD 7710 PS no rewerse?

[Kollebo]

Hello

I have a 7710 -97
suddenly reverse gears just stop working?
no noise or anything from the gearbox but the tractor moves just a little forward when i take the shifter to any of the reverse gears.
never moves backward just wiggles a little forward.
is there any electric valves that should open or how does the selection of reverse gears work?
Have anyone had the same problem?

Thanks C-J from Sweden.

 

[rockcreek4630]

You have electrical,hyd,and mechanical
with that trans. You will need books and
start testing to see which system is
giving you problems.