Re: Ultramatic - 1950 Transmission Fluid

Posted by Owen_Dyneto On 2011/12/7 13:03:04

I'm certainly no expert on rebuilding Ultramatics or even diagnosing their problems. I've tried my hand on two back in the 60s and 70s with mixed results. I had the 56 Carib done last year by Ross Miller and couldn't be more satisfied.

Let's remember, as these cars fell out of service as front-line transportation they were often bought for cheap transportation, probably by a succession of owners who progressively paid less and less attention to maintenance. And most were finally abandoned when they simply failed to go - usually motor or transmission problems. Some "repairs" might have been attempted, some of which probably qualified as butcher jobs.

There's a large range of meanings to the word "rebuilt". IMO any attempt to diagnose Ultramatic problems should include a full pressure test regime. If all a transmission required was the replacement of "soft parts" like bands & clutches, anyone with decent mechanical skills or a local trans shop could replace them, call it "rebuilt", and have a successful result. And if you're that far into it, you'd be foolish not to replace the bushings as well. But if you trust it to a run-of-the-mill transmission shop and the problems are deeper than that, almost certainly the rebuilder won't be aware of what to look for in terms of the many upgrades both by the factory and that have come to pass more recently; elimination of the wave washer in 1956 torque converters, drilling and pinning fulcrum arms to shafts instead of relying on taper-headed set screws, upgrading the parking pawl and shaft, hardened replacement rear pump drive sleeves, 40-spline pump rotor replacing the 20-spline unit, and many more. In the case of my 56 it had been serviced before and had a 1955 input shaft installed which is not compatible. Additionally the shaft was scored sufficiently to require replacement. A prior "rebuilder" didn't have a clue about these matters. How many of this type of thing is a local shop likely to be aware of and resolve? So my point is, don't assume a replacement of soft linings and bushings will necessarily constitute a properly rebuilt transmission.

Packard put a lot of effort into continual upgrading of the Ultramatic; an interesting review of their early teething problems as compared to early PowerFlite, PowerGlide, Dynaflow, Hydramatic, etc. (all of which had some very significant early problems) can be found in Lloyd Storm's article "Ultramatic Drive - the Case for the Defense" in The Packard Cormorant, Issue #42.