T90A Main Drive Gear Assembly

Yarder · Post by **Yarder** » Fri Oct 12, 2012 4:05 pm

I successfully rebuilt my entire transmission! Thanks for all the encouragement and advice from everyone here!

I posted the assembly and installation of the Main Drive Gear and Main Shaft Assembly on youtube. Please feel free to make any comments there if you think I might have done anything wrong. We installed the needle bearing dry, and you can see in the video at an angle, THEN added the assembly grease to hold things in place.

http://www.youtube.com/watch?v=HxvNyW42 ... e=youtu.be

Hope this helps out others here!

(As soon as I get the rig back on the road, I'll post another of video of that too!)

Xamon · Post by **Xamon** » Fri Oct 12, 2012 6:02 pm

interesting video, could be very useful. I have to take mine apart. What size were the allen keys for the oil slinger? I can't seem to find the right one in my tools.

53a1 · Post by **53a1** » Fri Oct 12, 2012 9:14 pm

Very well done. One question, did you find that the main bearing on the input shaft fit loose in the case? I noticed mine was very loose when I changed my input shaft felt seal.

Bretto · Post by **Bretto** » Sat Oct 13, 2012 6:49 am

Mine was a tad loose as was the new bearing.
Yarder, nicely done.
Unless I missed it or you just didn't show it, did you install the 2 radial springs under the 3 pawls?

Yarder · Post by **Yarder** » Sat Oct 13, 2012 10:53 am

Yes, I showed the two springs, each anchored in the same slot, and going in opposite directions.

I'll have to go check on the size of the Allen Key. I just grabbed a stack of them and stopped when one fit.

No, the input bearing was a very snug fit. It wasn't so tight that I had to bang it in, like I had to when I removed it. But I did have to slightly tap it in by hitting a piece of wood with my hammer. I judged the distance by having it come flush to a channel where a snap right might would fit in. There was nothing in the Military manual about putting the snap ring in, and I got one with the rebuild kit, so I didn't install the snap ring on the main input bearing.

Post by **wesk** » Sat Oct 13, 2012 3:37 pm

The snap ring needs to be on that front bearing.

Yarder · Post by **Yarder** » Sat Oct 13, 2012 3:46 pm

Oh poop. I hope you mean the interior snap ring and not the exterior one that surrounds the exterior part of the bearing that probably ensures the correct depth, or to prevent it from going into the transmission too far.

The old bearing did not have that groove for a snap ring.... so, after searching the manual, I assumed that I didn't need it.

Post by **wesk** » Sat Oct 13, 2012 7:59 pm

The front bearing outer race should have a groove for the snap ring and the ring needs to be in that groove to control the bearing float. The old bearing was probably a substitution that was not properly researched.

Did you review these two very good rebuild guides?
http://www.willystech.com/wt/T90Rebuild ... ebuild.htm
http://www.novak-adapt.com/knowledge/t90_rebuild.htm

I am referring to Item 4 in the drawing below.

Yarder · Post by **Yarder** » Sat Oct 13, 2012 11:35 pm

Thank you, Wes. I should really say, that you Wes, Sir.

Well, what do you know. Yup, I had both of those web sites printed out, and the TM in separate 3 ring binders on the bench turning page by page. I read the one referencing installing the bearing with the snap ring out, and I looked at the wrong snap ring.

So, now I have a main input shaft with the bearing exactly as shown in the picture, installed 180 out.

You won't be seeing any driving videos anytime soon from me.