UPDATED! Next trans question:

I am not an expert on transmissions but - nothing that spins fast should have side to side pay in it.  It seems that side to side play in the input shaft would cause the Main shaft (and the input shaft) to move and change the mesh of the gears with the cluster gear.  The front bearing is probably warn and / or the needle bearings at the interface between the input shaft and the main shaft.

There has to be an expert - who could give a definitive answer.  

So I want to update my trans rebuild.

At first, the trans was difficult to to shift into second - up and down. I rolled with it because I read a number of posts between CJ2A and 3A forums that it was common for a new synchro assembly to be tight, but that it would wear in.

It eased up after about a thousand miles or so, but instead of shifting normally it either needed a hard push to go into second or it would flop in with a quick grind. Pulling back to neutral for a re-try didn't usually help.

Now at about 5000 miles, it grinds into second gear every time. For about a week I could double-clutch second gear and avoid the grind, but that's not working any more either.

I have the top off the trans and there's about .005" end play in the main shaft - i.e.: the output gear is on, the nut is tight and the shaft moves.

In addition, the clutch collar engagement teeth on the brand-new second gear are shot, second gear has about 0.012" of end-play on the shaft itself (in addition to the play in the mainshaft), and the entire (new) synchro assembly moves on the mainshaft.

ALL of these parts were brand new. The cluster gear, the input gear, main shaft, synchro assy, second gear, bearings - literally everything except reverse, the reverse shaft, and first gear.

When I received the parts, second gear wouldn't even slide onto the mainshaft. I had to hone the bushing to get it to fit. In the end, I managed to get 0.003" of end-play with no other movement.

The blocking ring for third gear wasn't round - it was flattened a bit and I wasn't sure it would work. Once the trans was assembled, shifting second to third and back was extremely difficult without the shift cover, but it could be done.

In the end, I blame myself. I avoided brands I know are crap but still opted to build the trans with obviously out-of-spec parts.

I'm hoping to pull the trans and t-case this weekend and replace the synchro assembly and second gear with the best of my used parts. You know, those parts I opted not to use in the first place.

On a side note, I purchased a new speedometer at the same time. It's the same brand as all the parts above. It's crap too. Over the course of an hour drive on flat roads, the analog speedometer will show several different speeds for the same GPS-indicated speed:

50mph actual speed will show on the speedometer as anything between 48 and 57mph. Analog speed doesn't change while holding a GPS-indicated speed, but it's different every time I accelerate to 50mph as indicated on GPS.

For the record, I do not expect an analog speedo to agree with GPS. Especially when running larger tires. But I do expect the speedometer to read consistently - if the speedometer reads 57mph for an actual 60mph, then I expect it to read 57 every time my actual speed is 60.

My apologies for the rant, but I'm at wits end. I can't afford to replace the parts I really couldn't afford to replace the first time.

-Les

but plenty of both to do the job over ???

Do the job once, do the job right.