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Restoration Of The Transmission

Updated: Jul 19, 2022

We strive for perfection in our work. The restoration of the massive Simplex four speed transmission was not particularly difficult although there were a few glitches along the way.

The transmission was far too heavy to remove by hand! After careful consideration and discussion, we agreed to lift the vehicle and use a hydraulic engine hoist to support and then lower the transmission during the removal. The transmission had to be removed before the engine.


The transmission coming off the hoist carriage

Outside view of the transmission case with clutch adjustment cover and shifting / emergency brake cap removed

Note: the service brake assembly and forward universal joint housing are still attached

Transmission with side cover removed for beginning inspection and cleaning

Inside transmission with shifting rails removed

Transmission side cover and attached emergency brake actuator with arms after cleaning

Rear main shaft bearing retainer and bearing before cleaning

Reference picture for reassembly

Shifting rails in the process of being removed

Note: Both arm slots which are moved by the shifting cane

Reference picture for reassembly showing high quality forged steel shifting rails and integral forks

Shifting detent spring and ball

Transmission with main shaft, sliding gears and shifting rail shafts removed

Pilot shaft with clutch brake

Counter shaft during removal

Note: Reverse idler gear and shaft are still in place

First gear with a broken tooth, a new gear was machined and hardened as a replacement

Transmission / clutch case after thorough cleaning. After careful masking we coated the inside of the transmission case with Glyptal.

Forward view of transmission / clutch case

Inside of transmission case after application of Glyptal

Pilot shaft and clutch brake after restoration

Pilot shaft and main shaft after restoration

Countershaft bearing retainers

Transmission parts after restoration

Countershaft assembly

Countershaft and sliding gears

Transmission with countershaft, mainshaft, and gears assembled

Transmission fully assembled without covers

Transmission fully assembled including shifting and emergency brake levers and ready for installation

Left side view after installation

Right side view after installation

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