Transmission Restoration

 

 

The New Process 540C

The New Process 5-speed transmission is a selective synchromesh type with five speeds forward and one housed in a cast iron case. A 9" x 2" band type parking brake is mounted on the rear of the transmission and standard S.A.E. six bolt power take-off openings are provided on both sides of the belly of the case. All gears are helical with the exception of the first and reverse gear and synchromesh action is provided in second, third, fourth and fifth gears. The main shaft, countershaft, reverse idler shaft and all gears are machined from alloy steel and carburized for durability. In addition, all gear teeth are shot peened for high fatigue resistance.

The main drive or clutch gear is supported by a single row ball bearing mounted in the front of the transmission case. The main shaft is supported at the front by roller bearings located in the hollow end of the clutch gear and is supported at the rear by a single row ball bearing located at the rear of the transmission case. The countershaft is supported in a single row ball bearing at the front which takes thrust load and by a roller bearing at the rear. The reverse idler cluster gear rotates on two steel backed bronze bushings which are a press fit in each end of the gear.

Pin type synchronizer assemblies are used. The synchronizer assembly used for second (2nd) and third (3rd) speeds consists of two inner synchronizer rings, or cones, and one outer synchronizer ring, or plate. The synchronizer for fourth (4th) and fifth (5th) speeds consist of two inner rings, or cones, and two outer rings, or plates. Shifting is accomplished by a floor mounted gear shift lever attached directly to the transmission cover.

The image below is a cross sectional view of the New Process 540C 5-speed manual transmission as depicted in the 1963 Chevrolet Truck Shop Manual.

 

  

 

Initial Prognosis

When I first purchased the truck it was more or less fully operational. I say "more or less" because it did have its fair share of spliced wiring, oil leaks and other small band-aids to keep it running, but it was in drivable condition. True, I did experience a problem with the 2-speed rear axle; however, after rebuilding the Bendix Hydrovac I'm almost certain that that problem was related to a poor vacuum to the rear axle shifting diaphragm. The New Process 540C 5-speed transmission displayed good shifting characteristics and was tight even though it is 40 years old. Nevertheless, after removing it from the truck I could see plenty of Blue RTV Silicone Gasket Maker around the output shaft and also the Chelsea Power Take-Off assembly. After removing the transmission cover (#25) it appeared that the shifting forks, shafts,  gears and everything else on the inside were in very good shape. Nevertheless, rather than do a mere cosmetic repair (i.e. clean and paint), I decided to overhaul the transmission.

Research

The following information was found on the transmission case (#44) . This information was part of the actual case casting as opposed to being on an attached data plate:

 

     NP

     12-8-55

     C91171

     AL

I found myself back on the web looking for a source that would have an overhaul kit. Finally, I discovered DT Components, Drivetrain Products, a company specializing in overhaul kits for drivetrain components. After navigating the site I came to the page with the New Process Heavy Duty Transmission Kits.

  • It is important to know that DT Components does not sell to the direct public. However, when you enter your state of residence the site will automatically give you the name of your local customer service representative, complete with phone number and e-mail address.

I contacted the customer service representative for Colorado and explained that I was doing a restoration and needed an overhaul kit for my New Process 540C; specifically standard kit number TRK-27. I was subsequently directed to Western Truck Parts in Denver, Colorado, an establishment that sells to the general public. I gave them a call and they indicated standard kit number TRK-27 was in stock, so, I took a drive up to Denver and bought it. The kit contained all new bearings, retainers, seals and gaskets for a complete overhaul of the transmission.

Preparation

I did not want to gut and then rebuild the transmission on the floor. Further, having it on a bench would make it too high to work on comfortably. Since I fabricated an engine stand I decided to build an adapter that I could bolt onto the side-mounted PTO opening and then slide into the engine stand. Using the PTO housing as a template I fabricated a plate that would bolt onto the case in place of the PTO assembly. Next I turned down a piece of 1" cold rolled steel solid round stock to 1.460" so that it would fit into the engine stand. After achieving the correct diameter one end was cut at approximately 15 (the approximate angle of the PTO opening on the bottom of the transmission case) and a hole was drilled in the opposite end to facilitate a handle. The end with the handle was drilled and tapped to accept a " x 13 bolt to secure the handle. The shaft was then welded to the adapter plate to finish off the fabrication. The images below shows the adapter assembly holding the transmission in the engine stand.

                

 

Disassembly

 

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