I need reverse (auto tranny)

I know that this may a long shot but here goes.
A few days ago I put a new locker in the rear diff of my dodge ram plow truck. It worked great and I was able to plow snow in my lower driveway where I had not moved the snow in a long time. Well I got stuck which I more or less expected and asked a buddy to come and give me a tug. It was when I was being pulled out I realized that I could get my truck to spin the tires forward just not in reverse. Now I am very stuck with a buch of unplowed snow infront of the truck that I can't push through. My buddies can't get the traction they need to pull me out back the way I came. Is there anyway to get reverse back just one more time? I have thought of adding some sort of trans additive or just about anything else that can get me my truck back without waiting till spring for the snow to melt.
Everybody I have asked tell me that if's an auto I can't do anything.... I hope someone has a trick or two..
thanks

p.s. The last trans lasted me 13 rough years so I know it's time for a new one,, but first I need to get it to the upper part of the driveway.

Fluid level?
Smell burnt?

auto or stick?
If it's an auto you might look at the book for it and see if the bands need tightened. I know my old 727 was a pain and needed the bands adjusted every couple of years. Of course my neighbor with the same rig never had to touch his, go figure. Might try taking it out of 4wd to back up. Might be a problem in the transfer case.

fluid looks normal, seems to be the tranny, spins wheels in forward gears not in reverse. My neighbor said he would bring his tractor buy and I am hoping it wil have the traction and tourque to pull it to the upper dirveway. I will not know till next week when I am off and have time to play with it again.