[blykins]

I think what has happened is that it's been stood on its nose during shipping and it's got the blocking rings mashed against the gears. I've assembled Toploaders before and have had this happen.

It's a real simple fix, but 1. You have to pop the top cover off, and 2. You shouldn't have to do all this crap on a new trans.

However, if you remove the top cover to the trans, look at the blocking ring for 4th gear (the one against the input shaft). The blocking ring will be either cast iron or bronze....I think it's cast iron in a TKO.

Anyway, it's probably been shoved too far up on the friction cone on the input shaft, so just take a flat head screwdriver and gently get in between the gear and the block ring and move the blocking ring away from the gear. It won't move very far but it will be enough to free everything up. While you're in there, take a look and make sure everything else looks kosher and give her a turn in gear.

If you need help identifying a blocking ring, let me know.