Not enough torque

Not enough torque
4:1 additional reduction

After getting the electric drive components and battery connected, I found that the brakes and wheel drums were frozen, and the wheels could not rotate. I removed and freed up the rear brakes, and got the wheels to rotate freely. The front disk brakes were also frozen, so they were disassembled and made to work with much difficulty. The splitter valve for the brakes was broken, and the master cylinder had a vacuum leak.
When all was said and done. I routed the master cylinder output directly to the front drivers disk brake assembly (the only one that worked). The first electric run was disappointing, as the motor running with the max 400A that the controller is capable of, was just able to push the truck on flat grass. Once I tried to climb even a slight hill, it just gave up.
Based on the amp/torque curves for the CM77 motor, I should have been producing about 37 Ft Lbs. The CM77 output shaft is not designed for side loading, so it is not a good option for a chain based torque magnifying system.
I purchased an 80 tooth chain sprocket, a 20 tooth, and 12 tooth smaller sprocket and a bearing so I can make an additional chain speed reducer.
The e-tek motor running at 200A produces ~19 ft lbs, so if I use the 12 tooth drive sprocket with the 80 tooth large sprocket, which is a 6.6:1 ratio, I should be in the 125 Ft lb range which I estimate should be sufficient to move the 8,000 lb truck around my yard.
I may be able to walk faster than it will move, but thats fine for around the house.
Why is it never easy?