Jondburke

I have a 1987 gl10 turbo awd with Atransmission that has gone out. When it went out I could still push the 4x4 button and the rear diff would work but now that burned out too. Can't go anywhere now. Tranny shop said it was the final drive assembly that had gone. What should I do? Does anybody have a final drive for this car or is there an easy conversion to 5 sp manual for this vehicle? The engine runs great and we need the 4x4 to work. Thx for any help u can be