A833 Four Speed Gets Stuck in Reverse

With your left hand,push the cover up towards the floor as hard as you can, until the rear wheels come off the ground, then tighten at least two bolts.Then relax and tighten the others. Kidding!
I bet the two special long-shouldered bolts are missing or in the wrong holes. You remember those special bolts? In the absence of those bolts, post #2 will work. If it still occasionally gets stuck, push the cover up hard and cinch it up.