A500 / 42RH OD-unit rebuild

A500/42RH OD rotating assembly
A500/42RH OD rotating assembly

After the transmission it was time to tackle the overdrive-unit.
This unit is the 4th gear (overdrive) in the transmission, and has its own set of clutch plates. Overdrive can only be ‘selected’ with the transmission running in 3rd gear.

As with the transmission unit itself, there was almost no concerning wear to be noticed in the overdrive unit.
The OD-unit will also get Alto Red clutchplates and Kolene steelplates.

One of the little governor weights showed some wear, which was common with the early models. I managed to clean up most of the wear.

To disassemble the overdrive-unit, a very big internally mounted spring with over 800 lbs of force has to be compressed to be able to remove 2 snap rings.
I made a tool from the flange-end of a Chevy rear-axle to securely compress the OD-unit in a press.

With all the clutches and seal replaced and everything lubed again, the rotating assembly of the OD-unit was put together again.

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