No Second Gear At All

Freshly rebuilt trans using old parts that looked decent. 

Possibly broken or missing syncro springs or broken dogs in the syncro hub are not letting the syncro collar engage the second gear. This could be checked by taking the cover off the transmission and trying to manually shift the collar onto the second gear. If it binds before engagement then the syncro assembly is suspect. The replacement of the whole 2nd/3rd syncro assembly is probably the best way to go for reliability...and if I did that I would also replace the second gear if it already hasn't been done.

Ok, does the shift fork move back and forth on the shift rail? In that case it would be a roll pin problem. The shift tower may have to be worked on. There could be a problem with one of the poppet balls or the 2nd/3rd shift rail

The good news is that if you can put the 2nd/3rd shift collar into 2nd gear by hand then you have more or less isolated the problem to the shift tower and won't have to pull the transmission/transfer case.

Let us know what you find.

Whoa...I interpreted your post wrong. I thought you were talking about the 2/3 shift shaft and you were talking mainshaft.

Whole other ballgame! Yes, it could be a fore-aft mainshaft issue; however, it would be somewhat unusual for the transmission not to at least partially engage in second gear...perhaps grinding a bit and then completely out of gear.

What bothers me is the short throw when shifting to second gear...you said that it felt like only a 60% movement, but no engagement.

If it is an endplay problem that is going to require some teardown. If it is the shifter, it won't...or it could be a combination of the two.

What problem caused you to go through the transmission in the first place?

Once the transfer case is mated to the transmission...and the mainshaft gear installed, I don't think the mainshaft in the transmission should move back and forth. Make sure your mainshaft gear is seated all the way against the bearing and is tightened up.

The mainshaft gear is the one that ties the transmission to the transfer case intermediate gear.

That said, you may still have an issue with too much clearance between the transmission input shaft and the mainshaft. If so, this is a sign of worn out transmission parts.

Edited by athawk11 - 27 Mar. 2017 at 12:48am

So, I looked at the intermediate gear nut (the one that goes between the trans and t-case), and it was hand loose (I forgot to tighten it, apparently). 

Edited by cavalier - 27 Mar. 2017 at 3:23am

I should mention that most of that slop is gone now that I torqued down the intermediate nut (I did drive it with that nut only half-loose, so I'm not sure what that could have screwed up).

In your video it looks like the points of the chevrons on the teeth of the 2nd gear are worn off. They should be a pretty sharp point. They may have gotten damaged from your main shaft floating around due to the loose nut. This also might have been what caused your metal shavings. Without good pointy chevrons the collar can't grab onto the 2nd gear while it's spinning.

You could also have a little more gap between the mainshaft and the input shaft. Look at this drawing, part number 43. If this spacer is worn you might need to put a shim or two behind it to move the mainshaft forward so the collar doesn't have to move so far to the rear to fully engage the gear.



If you look at this short video where I was showing an issue with my synchros, you can see the sharp points on the chevrons of my brand new 2nd gear.





I hope some more experienced heads will chime in. This is what I see could be your problem, but I have only had two transmissions apart.

Good luck.

cavalier wrote: The shifter isn't able to grab second gear when it's stationary either, and yet I can shove it on by hand. -David

Right, it makes sense in my mind. The point on the chevron is gone, likely some of the inner teeth or splines in the collar have also been ground off so now the teeth in the collar can't reach the teeth on the gear with the limited throw of the shift fork.

A new 2nd gear, probably a new collar, and maybe a shim behind the spacer I mentioned above to move the mainshaft, and the 2nd gear that rides on,it forward so it is within reach of the throw limits on the shift fork.

I always put a disclaimer on my comments due to my limited experience, but if those chevrons are not pointed, it's like trying put your jeep on a trailer without a ramp. It just bangs into the bumper and never goes up. Add a little length and slope to your trailer with a ramp and it slips right in there. Add a little slope and length to your gear with a pointy chevron and it slides right on.

If more experienced folks think I'm pointing down the wrong road, please speak up.