Problems rebuilding HDS 3 speed transmission

I've started work on rebuilding the 3 speed HDS model transmission for my 1937 D-2 (worn front mainshaft bearing mainly, and lots of tar like residue coating the parts). Does the group have any collective wisdom in their transmission work on dealing with these issues I've run up against? I might post this to the K series forum since it uses the same model of transmission.

1) I can't remove the front main shaft. According to the IHC manual it says to drive out the countershaft allowing the countershaft gear cluster to drop in the case, thus allowing room for the mainshaft to be withdrawn from the case. However, try as I might I haven't been able to get the mainshaft to clear the dropped countershaft gear. The gear appears to be at the very bottom of the case. The synchronizer teeth on end of the mainshaft look like they still need an additional one eighth inch of clearance. Any suggestions or am I just missing something that's obvious.

2) How to pull the front and rear main bearings? Since the bearings are shaft mounted the drive force will need to be on the inner race. However there does not appear to be room for a bearing splitter to "get behind" the bearing and get the driving force on the inner race?

3) What kind of tools do you use to remove and reinstall the snap rings, especially the plain small one in front of the mainshaft bearing? It's about one inch in diameter and typical snap ring pliers aren't strong enough. Googling this didn't come up with anything useful. Maybe I'm not calling it by the right name.

Thanks for any insights you folks can provide.

I "think" I'm making progress. If I remove the front main bearing the mainshaft will come out by tilting the back up and over the countershaft gear. I noticed the bearing is not a press fit to the shaft! When I get that heavy snap ring removed it hopefully will come off. I'm getting a pair of heavy duty Stanley Proto snap ring pliers on Friday and we'll see how it goes.
Wish the IHC manual was more specific but maybe in the 30's they had high expectations for mechanics to figure out what needed to be done!
At least the D-2 doesn't have a check engine light.

You are probably on the right track about the bearing removal. Some transmissions have a flat spot milled on the syncro collar that allows the input shaft to be removed in that position only.

I finally got it apart. The International service manual is a bit misleading. After you drop the countershaft gear and partially remove the input shaft by pulling forward, the next step is to partially remove the mainshaft in the rear direction. Then the input shaft, with bearing attached, can be tilted up and over the front countershaft cluster gear. Then, to remove the mainshaft pull off the rear bearing and bring the mainshaft forward through the case. I did not remove the second gear off the mainshaft because of the ferocious looking lock ring!
Other lock rings were removed with a stout Stanley Proto J250G lock ring pliers. Bearings were pulled with a Harbor Fright bearing splitter and puller, but the bearings are not going to be re-used.

YEA !!