1981 CJ7 Restoration - 2020.04.18

Today we begin to disassemble the transfer case. I've been kind of dreading this day since this piece of machinery weighs quite a lot, but why not sack up and get it done?

I have to give a shout out to Mr. Paul Gangialosi who posted a 2-part tutorial on taking apart and rebuilding the Dana 300 transfer case. His videos are very informative and thorough - a very valuable resource for the home mechanic. Thank you, Paul!

Dana 300 transfer case rebuild Part 1 by Mr. Gangialosi

Dana 300 transfer case rebuild Part 2 by Mr. Gangialosi

The transfer case is a Dana 300, one of the more popular transfer cases for the era of American off-road vehicles and still in use today by many purists, though heavily modified. The Dana 300 was reputed to be a very solid and durable transfer case, with one major weakness - its rear output shaft. Those who do heavy off-road driving with low gears and high-output motors have experienced breakage at the rear outputs shaft which leaves them stranded. Being that this vehicle will not be doing anything crazy off-road, I hope a stock output shaft will work just fine. The one in there has done fine for over 91,000 miles and 39 years.

The transfer case was an absolute disgusting mess. There was obviously a leak and this unit was covered top to bottom with thick, filthy grime. There was also considerable rust.

Prior to degreasing - note the 2 tags that were attached at  to the bolt holding the intermediate shaft tab. One is a serial number - not sure what the other one is.

Once I got the bottom cover off I could see inside. Things looked pretty good. Obviously, the gear oil was a mess - old, dirty, viscous, however, the gears and everything else looked nice.

Looks pretty good except for the old gear oil.

After knocking out the intermediate shaft, I got the intermediate gear assembly out. It houses 48 needle bearings, two sets fo 24 separated by a center spacer, then enclosed on both ends by end spacers and thrust washers.

Intermediate gear assembly and needle bearings.

Wanted to be sure I noted the position of the speedometer gear assembly. In a previous post I described how much trouble I had with the bolt that holds the retainer (not shown). It's very important to not the position of the offset gear shaft as different positions around the clock are used based on the size of speedometer gear uses - in case larger than stock tires are used, or if the differentials are re-geared.

Speedometer gear assembly orientation.

Taking the rear output shaft tail housing off, I noted a couple of thin shims. I believe they are in place to set end-play, of which there should be none. Will have to remember this orientation when I reassemble this sub-assembly.

Rear output shaft end-play shims.

Well, I got the transfer case about 70% disassembled. Will get back to it soon.

Partial disassembly.


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