Wont Go in Reverse

avoid corners?

Check...

Fuses, limit switches on the controls, contactor coils and grounding.

"avoid corners?"......and dead ends!

But seriously, I can think of a few things to check:

1. The forward/reverse shifter, check linkage to switch and check switch itself.

2. Check the reverse solenoid.

3. Check the forward/reverse interlock (locks out forward solenoid while reverse solenoid is pulled in and visa versa).

4. If you have a double winding traction motor, check for an open reverse winding.

5. Check wiring, fuses, and circuit breakers between all points listed above

Off the top of my head, this is all I can think of. It's been a few years since I serviced one.

It is an electric fork lift, it must be an electrical (directly or indirectly) problem.