Hahn
To get the mainshaft out, you must pull the rear bearing off the shaft first. This requires large snap ring pliers, and either a long puller or I just stood the tranny on it's nose(input shaft) and then used a couple long screwdrivers on opposite sides of the bearing and pried against the case a bit at a time till it came free.
Once the bearing is off, you can then lift the shaft out/up from the case. There are about 15 roller bearings that will fall into the case when you separate the input/ouput shafts. If you want to prevent this, then you must take the input shaft out the front first, and as you separate the 2 shafts, you kinda wiggle your finger in there, you have to find a washer and push it towards the input shaft as you separate the 2, and all the bearings will stay in the input shaft end. Once the input shaft is out, there is one synchro ring(4th gear synchro) that will be loose, and then the output shaft will lift up/out and nothing else will fall out or be free.
..Here's a pic.. of the 2 shafts separated. You can see the tiny washer on the left part ( the output shaft), and you can see the 4th gear synchro on the input shaft which is on the right.
Other than replacing the synchro's, there's not much else you can rebuild in there.
The countershaft has a ton of bearings that are unlikely to be worn unless the tranny has millions of miles on it. I'd just leave it alone unless you're a sucker for punishment.(I did use a custom made broom handle piece of stick to do mine, and I still have it if you need it!!) Maybe spin it once the rest of the stuff is out, and if it spins nicely with no roughness, then just leave it alone.
You can take the side covers off i you need to get access to the case. When you put it back together, new in/out bearings, and I'd probably see if you can get new bearings for in between the in/out shaft. I've probably got some laying around here if you need some I could give 'em too you, but again, unless they are obviously worn or pitted or something, they're unlikely to need replacement. You'll see what I mean.
Finally, when you put it all back together, there are spacers you can get that allow you to adjust the endplay of the shafts and gears in there. Getting this right will make a huge difference to how "tight" the tranny will feel later, and how well the synchro's work for you. Too much play, and it may grind when trying to upshift, or pop out of gear, and too little play will make it difficult to impossible to upshift...
There are special 11 ball-bearings available for the input shaft for the diesel as opposed to the 8 ball-bearings used on the gas T-18/t-19's. Might be worthwile to see if you can find these.
Keep it clean, lay out all the stuff as it comes out, label things so you don't forget later what they are, and it'll all come together nicely.
..another pic.. There's a few pieces, but don't be intimidated. I'd never done one before, and I did 2 in about 2 weeks and both of them worked fine after, so if I can pull it off, anyone can...
That's about all I can think of off the top of my head this morning. Other stuff might come to me later...
Zigg
Thanks for that PDF.
