working on my MIL tractor, and not sure if this is related or not..as did not know this was a issue, she was low on hydro and also since it has been "forever" since she changed the filters, replaced both hydo under the tractor and the one PS filter.. and the hydo works fine, but the 4 speed shifter will not disengage to another gear. the F/R works and the HI/MED/LO shifter works, but all in the one speed on the 4 speed shifter. it flops around.. like no care in the world.. any ideas? I know it is not low on fluid, in fact may be a little full, the site glass is full... I am pretty sure I did not do it when I changed filters. but who knows.. need to fix it now.