I recently picked up another bronco. 1971 351W, c4 transmission, Dana 20 transfer case and factory 4.11 gears in the axles. 35x12.50x17 wheel setup on Duff 5.5 inch lift. When I place in park on the slightest incline, the entire bronco will roll almost 18-24" before "park" catches and holds the bronco in place. Just seems very excessive amount of play in the transmission and/or transfer case. I have just rebuilt the rear end (bad axle bearing and brakes) so pulled the third member and everything looked good in it. My 1975 bronco with 37's had a similar build did not have this much play in the transmission /transfer case. Any suggestions why it has so much slack in it?