After I got the helix gear thing sorted out, assembly is relatively strait forward. As per the maintenance manual, assembly starts from the bottom and works upward. It is important to remember which of the bearings use snap rings and which don't. The manual has images for the snap rings but the written description doesn't always mention them. In an attempt to make a leak-free case (if that's really possible with these old gals), it was decided to sleeve all of the yokes. Sleeve vendor recommendations mention using an epoxy putty to flatten the gouge made by the old seal. Fortunately, the sleeve from a 1970's something GM car has the same dimensions as the t-case yokes. These parts were sourced for a very reasonable price. There are many different philosophies in sealing up these gear casings. I use the old tried and true Permatex aviation form-a-gasket with pretty good success. The key is to get everything grease free including all of the threaded holes in the casing. When applying the sealant, I have found that if you aren't making a mess with the stuff, you are applying it heavy enough.
Image of sand blasted yokes with new sleeves being installed with epoxy. The epoxy work time is short so one has to have everything needed close at hand.
Sleeves used and part number. Also pictured is a decent part number for the t-case shifter fork seals.
Image of assembly of bearing retainers. Use plenty of sealant.
Image of back side of the t-case. Note the unique bearing retainer covers on this early model.
Oddly, the first run Chevy case has all of the same parts used in a later (mid 41+) truck with the exception of the two bearing covers shown in the image above. As noted previously, this t-case configuration was also used for the entire run of pole setting trucks that employed the large mid-ship winches. After buttoning the case up, the unit was filled with gear oil and rolled on its sides so that the seals got lubricated.
I called a buddy to help me just to lift the t-case off my work bench down to a dolly. Getting the case out of the shop and on my homemade transmission jack cradle was so easy, we decided to install the assembly on the truck. As luck would have it, we had the t-case bolted in in a very short period of time and effort. I love when that happens!
Hope you enjoy, and more importantly, I hope you all make some time to play with your trucks!
Paul
) when we were coming back from the MV show last year (twice). One particular river canyon, especially coming back home required me holding third for about a mile and a half, 1000 vertical feet (maybe a little less 
), and thirteen twisty turns. Maintaining 25 mph seemed to be just about right. At first I was thinking man, how’s this gonna go, but I just held her right there at 25, roaring all the way up the hill. No big whoop ! Even ran better after that ! I think my foot got heavier after that too. 
