SX 75 MORX75X436468 Rear Engine Rider.

[Toughtoad]

Greetings:
I am looking for TSB SIB-M87-30-3. Bulletin references power train hydrostatic. Using Tech Manual TM1391 JUNE 1988 and having done all adjustments recommended by JD. Mower is continues to jump out of gear especially 3rd back to 2nd, slows under light load or very slight incline. Performs well in higher gears 4th,5th,6th and 7th.
Before trying any R & R (parts are scarce because of vintage). Would like to read what this TSB has to say.
I've done an extensive search coming up empty. Under the impression JD hides these things from the public square or the age of the machine is a factor. Appreciative of any assistance given.
Respectfully,
Toughtoad

 

[bertsmobile1]

The gear change is held in position by a detent .
Not familiar with your actual machine & gearbox but usually it is a simple arc of holes that a ball bearing drops into.
Over time the ball wears a grove between the holes you use most often so it jumps out of gear .