Not sure I agree that the frame and other parts are unique to the Hydramatic.
Randy and I are currently rodding my own 55 1st Edition that came from the factory with Hydramatic, and the unique frame elements appear to be BOLT-INS. The required parts for either manual or auto were apparently installed as needed at thew factory, AND some items were installed on ALL frames. Mine for example has a bracket that appears to be for a clutch return spring.
Also, those with these original cast iron Hydramtics just should not assume they need a rebuild if they feel a little odd. They HAD quirks. For example, the 2nd to 3rd shift is really harsh because BOTH planetaries are being shifted. And, ALL the shifts are much "more abrupt" than on the wimpy modern GMtrannies.
One thibng I found: these old trannies leak like a sieve, BUT if you add the CORRECT amount of Lucas Stop Leak, they STOP and no ill effects result. The Stop Leak apparently saturates and swells the old dried out seals and stops the leakage.
Also, it is apaprently much worse to run these trannies with too MUCH fluid in them than not enough.
Jim G
