Not to sidetrack Coobies thread...but you better get under you tractor and check nuts and bolts on everything that keeps your tractor rigid, after reading your post I have tried to get my tractor twisted up to see if I have this problem....I can park it on anything, my doors open fine and do not change.
I did tighten all the loader/ backhoe subframe bolts, along with where they mount to the rear axle and cab isolator mounts after the first couple hours of use, I got about a turn to a turn and a half on most everything.
I exercised it pretty good yesterday for about 8 hours, I checked it all last night again, some of the loader subframe bolts I got about 1/8 to 1/4 turn, every thing else was still nice and tight. Things are starting to settle in. Ill check it all in another 8 to 10hours. I believe after the next tightening it will need it much less frequently.