A833 Four Speed Gets Stuck in Reverse

The problem is not in the detent. The problem is in the reverse “shoe”. The reverse shoe and 1-2 shift arm are matched to prevent the box from going into more than one gear at a time. There are 2 shoulder bolts that go into 2 tight holes in the side cover. These align the cover very precisely. Find the 2 shoulder bolts and put them where they go, I think they are in the center on the short sides of the cover. The worse scenario is someone put the 4 speed together with mismatched parts.