A855 - 5 Speed

Yeah I'm more inclined to think it's in the cover.I wouldda thought linkage but you seem to think that's OK.
>My first Go-To on that is; I would suspect the cover is too far back. Mopar covers are indexed to the A833 case by two special long-shanked bolts so this is not generally possible. But every once in a while a guy needs to pry the cover forward as far as it will go. IDK about Passon boxes.
>The next thing I would suspect is a loose external shift-lever on the stud. I usually fill that cavity with loc-tite before the special nut goes on; the one with the serrated teeth on the underside. Then after it dries, it will never wobble around on the shaft again. I use the low temp stuff, just in case I need to take it apart some day.
But there is one caveat; the loc-tite likes to migrate along the stud up into the cover, locking the works up solid. You have to prevent that. It can only wick up there until it is stopped by the O-ring seal; nevertheless, if it does, you will have to get out the torch and take it all apart for cleaning. No biggie; just time.After this, you would have to re-sync the neutral gate. And for street use, do not bias it.
>After that, the next Go-To would be a broken weld on the other end of that stud which would allow the internal lever to misbehave.

Once you have done the loc-tite thing to both the 1-2, and the 3-4 levers, you will be able to really slam that shifter about as hard as you care to, and the shifter will hold it's neutral gate for years. In fact, if you don't already have 1/2 or better shift rods, and it looks like you do, then they would be the next thing to change. But yours look pretty beefy and look to be in a nice straight shot. Just make sure nothing rubs on something it's not supposed to.

FWI; I don't see a shift stopper/over-travel limiter, on the shifter mechanism. If you plan on slamming the shifter often, then I think it would be worth it to install one, else the rooster-comb and interlock-pin are gonna take a heckuva beating