I'm fairly new to construction equipment, but have operated and repaired tractors my whole life. I purchased a 955L to clear some land and have run it for about 60 hrs after servicing and replacing some minor parts. After about 10 hrs the pedals felt spongy and i tightened the brakes. After tightening the brakes the machine quit moving. I found the transmission screen full of black fiber debris. I cleaned the screen and the machine ran another 10 hrs before the screen clogged again. After cleaning the screen a second time the petals got spongy again and after adjusting the pedals the machine will not operate properly. If you tighten the brakes enough to grab, when you depress one pedal the machine locks down. I'm wondering if this is a steering clutch, brake issue, a combination of the two or possibly something else?
That black fibrous material in the screen is burnt clutch friction material, and is probably the reason you have lost drive - although if you over-adjusted the brakes that could have been a contributing factor. What adjustment process did you use.? Post some photos of the debris to confirm, and a Serial number to help accessing technical information.