NEED HELP SL3 TRANSMISSION PROBLEM

HAVE SL3 WITH FAN 10TE-F CONT
Transmission has stopped transferring torque to spindle.
Can anyone out there tell me likely cause?
What actuates the gear shift and applies pressure to clutch pack?
I am wondering if the small trochoidal oil pump supplies pressure to do this, or is it for lubrication only?
We have no documentation for this old machine.
In the dark.

Thanks

AFAIK there are electrically actuated clutches, either 12v or 24vdc. The pump is for lubrication