Dana/spicer 20 rebuild

[Stuart_Snow]

I recently rebuilt my Dana/Spicer 20 transfer case from my 77 CJ-7. After 100,00 plus miles it turned out to be in remarkable shape internally, but outside it was a greasy mess.

I decided to use the Novack rebuild kit. I just happened to have a 5 gallon bucket of Pro Chem ferrous soak which took all the hard work out of cleaning the case. This stuff really works! I used a large steel tub and a propane burner for heat. Gloves and safety glasses are required as this is a highly caustic solution.  It eats away rust, scale, paint and grease in short order. The downside is you will have a tub of black smelly water to deal with afterwards. The rebuild was straight forward thanks to my CJ rebuild guide and my 1977 shop manual. Trial fitting and walking through each procedure mentally helped eliminate mistakes. There is a certain sequence to follow which I stuck to for the most part.

Setting up the front output shaft end play was a critical step which takes time and patience. A magnetic dial run out gauge really helped here. I think Novack makes a billet unit to replace the shims and help eliminate leaks. I used lots of sealer on the shims.

The one place I ran into trouble was installing the new Novack super hard intermediate shaft. "super hard" describes the installation process as no amount of persuasion from my dead-blow hammer could force it all the way into the bore on the front of the case. I finally found a socket that fit this bore size and gently lapped the bore with some super fine lapping compound. I did just enough to get the shaft to go in all the way. I did not have a shop press at this point but got one later when I did the t-18 rebuild. I was disappointed with my Novack instructions as they did not mention rebuilding the tail shaft assembly at all other than final assembly where it just says to reattach it. I spent a lot of time on this step setting up the pre-load with the various shims. A lot of trial and error was required here but getting it right is critical so i stuck with it until I was happy.  I used Permatex ultra-gray on both sides of all gaskets and sealer on any bolts that are exposed to the inside of the case. I'm hoping for no leaks. I'm happy with the results as the unit turns freely and has proper pre-load on both outputs plus its nice and shiny now to boot.

[Moses Ludel]

Helpful illustrations and comments, Stuart.  Those tackling the Spicer 20 rebuild will appreciate this!  Great photos, too.

For those seeking detailed, step-by-step instructions on this rebuild, I cover the complete rebuild of the Spicer 20, including bearing endplay shimming, in the Jeep® CJ Rebuilder's Manual: 1972-86 (Bentley Publishers).

Moses