If memory serves me correctly on left side of platform under the cover is the hydro ECM. There is a switch you can flip to take ECM out of loop and this allows you to operate the dozer controlling hydro manually .
What this means is dozer will operate like a skis steer hydro does. No brain to adjust the hydro to load automatically.
Try this and see it it moves. Your DC70 had the same over ride for ECM.