4 speed ka-booom !

Does your wife know you are bringing stuff into the kitchen?

Hey, I got a tip for you; Grab the tailhouse and slam it onto the case, but,upside-down.Align the cutout in the tail house, with the hole where the cluster-pin goes in. Do you see the interference? Do you know where I'm going? Hyup. If you spend just a few minutes with the die-grinder shaping the T-house, then the pin will slide right in.
To what purpose you ask? Well, It will save you a lot of frustration during the re-assy procedure.
I assemble the case with the cluster loaded(but without the pin), and reverse, and the loaded M/D in place.(I grease the washers to the case). I then stand the case on it's face, dropping the M/D into a hole in my benchtop, and letting gravity pull the M/D all the way down.Next I take a brass ring, and drop it onto the M/D.Next I push the cluster to the bottom of the case, as far away from the M/D as possible. Then I grab the loaded tailhouse in one hand, with its gasket lightly 3-M'ed on,and the 3-4 slider moved back almost all the way into 3rd, and insert the tail,upside down, through the back hole. With the other hand, I guide the M/S nose into the M/D and index that brass ring to the 3-4 struts. When indexed, I drop the tail all the way down, and align the tailhouse cutout with the cluster-pin hole. Then reach inside the case and gently pull the cluster into alignment, center the rear thrust washer and drop the pin in. Sometimes the front washer needs to be centered at this time.Then the woodruff-key, and drive the pin home.Finally,spin the T-house around (gently, so as not to damage the gasket), and bolt her up. And double finally, reach under the bench and push the M/D up so that the ring properly locates into the struts, and pull the slider down into neutral. The rest is yours.
If you try to assemble the 833 in the conventional way,(not standing on it's nose), You will have a lot of un-fun. It can be done, but I can almost hear the cussing from here, and if you bend that 4th gear brass, you won't know it until the roadtest. And there is room in the M/D cavity for two or three needle rollers to fit in there and you could never tell.
And don't use Vaseline to hold the needles in place, either.Unless,maybe,your garage is really cold.Naww not even then.
Well there you go, I gave up another secret.....