[Mark Yacavone]

Not enough frictions in the lo/rev, or not enough lining left on the one's there.
You may or may not be leaving on the lo/rev and the forward. Depends on who built it.
If it has an auto 1-2 , then it should be on the forward clutch pack only.
In your situation ,I'd say try it pay close attention to low and high gear.
Find a place to drive in and out without using reverse, and hope for the best.