1956 Travelall 4X4 Transfer Case Problem

[Bruce A. Frank]

A while back I related the process of "repairing" the output gear on in my NP201 Transfer Case in my "new" '56 S120 Travelall. To refresh, this gear is a two part with the inner gear and outer gear cushioned with captive small diameter die springs. The design didn't work and the failure of the springs was at a 100% rate. On my first S120 I rebuilt the gear once with springs and it lasted about 6 weeks, which was close to the durability of the OEM part. Oh, btw, the failure is so common that the gear is called the "knock gear."

My second try at repair was to weld the inner and outer gear together with some rigorous preheat and postheat procedures. It worked and I put 200,000 miles on the repaired gear without a whimper.

To make the repair on my current S120 I found a salvage yard that sold me one of the failed-spring gears for cheap. My intent was to make the welding repair on that spare gear and swap it with the one currently in the case. . .to save down time.

In the mean time I came across a "rumor" that the solid (one piece) gear in the NP200 transfer case could be substituted for the two piece gear in the NP201 case. Perfect match with no modification required.

I set out to verify the info and found a 4X4 parts/service center that had done the swap and said the rumor was true. But, they didn't have a gear. I spent the whole weekend searching virtually every transfer case discussion in the 4 wheel drive forums on the Internet. I found a link to an exploded view of the NP200 from a company that specialized in parts for old military and civilian Dodge Power Wagons. Company site http://www.vintagepowerwagons.com listed on the PDF. The pdf had a short parts list that included this gear NOS!!!

I just got off the phone with them where they also verified the substitution. Yes, the did have the gear New Old Stock! $125 and will be here in a week!

[WRENCH MAN]

I've got an old NP 20X? out of a Dodge, I would have sold it to you cheap,if it was the correct one?, and I could have even delivered it today!, I was in San Jose all afternoon!, sit'n on my but in Red Bluff right now.

[DavidWTravelallfan]

Isnt the purpose of the 2 peice gear setup so Low range and neutral can be acheaved? Using the solid one peice would limit the gear selection of the case.

[Bruce A. Frank]

This is the two piece gear. An inner and outer part with springs in-between. Springs get chewed up and the gear, with no cushioning springs, knocks as the parts slap back and forth at speed. This is the output gear. Its being a two piece or solid has nothing to do with high or low range. Other gears fit couple into the center for speed change. This gear is forged as part of the output shaft on the back side of the gear face you see. U-joint yoke bolts on the end of the shaft.

[Bruce A. Frank]

Here are the two gears. The two piece gear from the NP201 and the solid one piece gear from the NP200 Transfer case that I will use to replace the "knock gear" that is currently in the NP201.

I have been over the parts with calipers and micrometers and find all the diameters, lengths, tooth size, spline count, tooth count, and bearing bosses to be exactly the same. Just have to do it. Dates on the Mil Spec packaging was all 1955 and 1956. Was wrapped in vapor paper and corrugated padding cardboard.

[basdas]

I was reading this thread and was curious how one knows that all the guts from a 205 np will fit into the 201 np? Did you do a transplant of parts from one to another. Did you measure all the gears and bearings ? Any insight would be great.

Brett