JD 125 Automatic- hydrostatic rear end release pins inop

My father-in-law has a JD 125 Automatic with the two pull out pins/levers on the rear of the rear drive unit-- those two pins are not disengaging the rear end. He tells me this has made the tractor unable to move. I will be traveling there for thanksgiving and need trouble shooting ideas on how these pins work and what they do for the transmission and drive system. Help appreciated-- Genevatexan

http://www.uni.edu/peterson/John Deere 175 Tractor/John Deere 175 Hydro Service Manual.pdf

I know this is not your 125, operation should be the same. Pulling rod out puts transmission in neutral/freewheel operation manually. Be sure to check keys in both sides of rear axle for placement in shaft.