Re: Conversion of a ‘56 Ultramatic to a ‘55 400 & A Few Engine Rebuild Questions

Posted by HH56 On 2021/1/31 17:37:52

The trans can be reliable if it is babied provided it is gone thru and thoroughly inspected with all worn or questionable parts replaced. Ross can guide on that with his videos on YouTube and has also developed a couple of mods that seems to help the shift points to make the transmission more pleasurable to drive. IMO, It will never have the easy service and parts availability or performance and reliability of a correctly installed 700R4 if you are looking for a daily driver type situation.

One of the bigger downsides of having a Twin Ultra is that unless you plan on doing the work yourself, if a problem arises there are almost no local trans shops that will even consider taking on a repair job. Even among those Packard people who still work on them, the really knowledgeable service is limited to one or two people on each coast with NOS parts similarly constrained to one or two vendors. Ultramatic seems to be a bad word so of the few local shops that deal with older trans that might be willing to talk to you the Ultra, being a unique unit with different operating principles and characteristics or foibles other trans of the era did not share, is an anomaly. The mechanic might be a Hydramatic or TorqueFlite expert but unless he is is also very familiar with a comparatively rare Ultramatic he can miss something or worse, can do real damage to the unit. In that scenario any repair $$ will be wasted and you might be looking for a new unit.