Re: Repairing Ultramatic

Posted by BH On 2009/9/28 17:11:17

Of course, it's never a bad idea for owners to compare notes on what others have run up against with their Ultramatics, looking for the most common and relevant failures. Thankfully, topics from the SCs, STBs, and SSBs are neatly referenced (and hot-linked to scans of actual documents - where available) here, in this site's Service Index feature for 1951-54 and 1955-56 vehicles. Same for 1948-1950 is currently in the works.

Yet, the best transmission men that I've known (regardless of brand) have always run a comprehensive pressure test. Comparing the results against factory benchmarks helps them quickly pinpoint the problem area. (Sure beats those old cardboard diagnostic wheels.)

While most guys get by with a couple of gauges for most transmissions, there must be some reason for having a third gauge with the Ultramatic, but darned if I can remember. I've only ever helped replace a front pump seal that let go and had the torque converter apart for a quick peek in one of my V8s and cleaned the filter screen in the other two.

Having managed special service tools for a GM dealer, I have a feeling that many of the tools needed to rebuild the Ultramatic can be substituted with or adapted from more modern versions. However, I'd like to lay my hands on a set of those gauges in good working order and a complete pan adapter, as there are a couple of take-off points on the valve body that you cannot get to otherwise. The adapter had an aperature to run hoses to those points. It also had a rubber plug that could be removed to permit insertion of a pair of wrenches to adjust the throttle valve presure setting - though that is probably one of the last things that anyone ought to be messing with.