Dana Spicer aux trans

Traded for a Dana Spicer 5831 G aux. trans. Was told it has over/under drives which it doesn't. From what i've found on the net they were used in trucks before the 2 speed rear ends. It has 2 under drives of 2-1 and 1.31-1 also 1-1. Can handle 375 ft.lbs. of torque. Stright cut gears non sycnroed. I'll be puting in my truck a RM 400 Dodge motor home chasis with a 440, 727 trans, REO F23 cab. The question is can it be turned backwards? That way it will give me 9 high drives foward and 3 reverse gears. I'm looking for gas mileage 6-8 mpg is killing me. I won't even mind cutting a hole in the patio to shift gears. I'll monkey around to see which drive works best and leave it.

Years ago, I saw a f350 that had a automatic trans with a standard 3 speed trans mounted behind it. They used it in the woods, gave them extra pulling power. Not sure though if the gears would stand the torque if you mounted the trans backward. Sounds as you need something like a Gear Vendors overdrive to do what you want to do.[S

Hi REO,
I have often wondered about putting a transmission in backwards like that, but you have to be your own guinea pig on this one. Don't leave your main in gear and your auxiliary in neutral, though, because the countershaft won't be turning when driven backwards and in neutral, so the upper gears will run out of oil too soon. The way I've got the torque figured out, is you are driving the transmission from the other end so you would be putting the torque on the teeth on their other side, but you are also turning the shafts the opposite way because you turned the trans end-for-end, so the torque should be on the same side of the teeth as before. Those old Auxiliaries are tough transmissions so you should do alright. Go for it.