Lower Transfer Case Gears

A date of 1949 would make sense. That case is the original out of Thumper and he is an early 1950 3A. If I remember correctly the T90 that you have that came out of Thumper was also dated late 1949.

Like Bob W said, you have to install the intermediate gear first. I installed the slide gear fork first so that I had more room to get a wrench on it. Then, I installed the intermediate gear.



For this assembly, I am using the AA tapered bearing kit. One thing I don’t like about the AA kit is that it fixes the intermediate gear assembly to the rear of the case. I cut the counterbore in the intermediate gear spool to the depth called out by the AA instructions. After assembling everything, it leaves a .015 gap between the front bearing and the inner case wall. Since the gears are helical, in forward motion, the gear tries to pull towards the front., and since there is a .015 gap, I’m nervous that the outer wall can flex .015. For this reason, I decided to put a shim in between (see pic)

It would have been easier to put a shim behind the bearing cup, or better yet, just not cut the counterbore so deep, but these are the shims I had to work with.

This is what I was talking about earlier on clearance between the thrust washer and the output gear. I actually had to dress a little off the OD and chamfer the edge that sits inside the gear bore:





One thing that is very nice about this setup is they the output gear is smaller than the bores in the case so you can install and remove the snapping outside the case:







These gears are quiet when I spin them on the bench. “Silent but deadly”.



Barring any interruptions, I’ll finish this up tomorrow.

I plan to bring this assembly to the fall reunion if anyone wants to come and check it out.

.... sorry for the messy bench. It’s just how I work.

Edited by jpet - 02 Sep. 2021 at 6:53pm

A note about milling the lip on your shifter case, ... (or whatever you call it), you don’t necessarily have to mill off the exact same amount as the added washer. As long as the bearing is clear, you are good. If you are willing to spend time assembling and disassembling the case, you can mill the lip to a depth that ensures that the faces of the intermediate gear and output gears are flush.



I’m not sure if this has been mentioned yet but you will have to cut some off the 4wd in and out shaft,( or whatever it’s called).



... as is, the shaft will collide with the bigger gear when 4wd is disengaged.   I removed 3/8” off the end.



When 4wd is engaged, the end of the shaft still extends through the bore in the case.



Everything is together other than the guards:



One thing not pictured is that you will have to do a mod to the pan. The thicker gear collides with the inside of the pan on one bolt hole area. Simply dent the pan outward. It will be obvious when you assemble it. Once you do this, a hex head bolt will not fit. You can use a socket head cap screw.

Edited by jpet - 03 Sep. 2021 at 12:03pm

Personally I feel that NAPA GL1 should be totally sufficient.

My plan is to run GL1 in this transfer case just like in the transmission.  If you don't have a sealed bearing in the back of your transmission, some of the  GL1 from the transmission in going to end up in the transfer case.  GL1 has worked in the past in these transfer cases and I have destroyed gold metal parts with assembly lube (which is odd, but it happened after a year in storage).  So, I am sticking with the GL1 and not going to add the Mobil 1 variable at this point.

Thanks for posting Bob. I’m anxious to see these in use.

I’m no expert but I think it would be best to get some good road miles on these gear for break-in. It seems like the fastest way to lap in the helical gears and it puts all three under load. Too bad you can’t do a road trip in reverse to lap in the slack side of the gears :)

I also think it might be a good idea to change oil after 100 miles or so. I noticed on my first oil change that the oil had a slight grey hue to it which I assume is from the gears lapping in. Second time I drained the oil it was clean. Look forward to the updates.

New gears are in and work like a charm!  Story on my thread.

Grasshopper crawls with jpet's gears.

The Novak pan is deeper and holds more goo