Packard Forum Index » V-8 (1955-56)

Is there a vent hole on the ultramatic transmission. If there is, where can I find it and are they commonly clogged?

I had a big trans leak before, changed out the pan gasket, everything stopped and there was no leak after I filled it back up. Then I ran it a once or twice, no leak. Now I back it up in the driveway and there is a leak. It is coming from above the gasket somewhere on the main body of the trans. The fact that it did not leak before and now is, to me says a pressure leak, but I am no mechanic.

Any help?

There is a vent shaped like an elbow screwed into the left side of the case about halfway up. I have never seen one plugged up, tho running the trans up to 60 in low might make it come out there.

The more typical leaks are band adjuster screws, selector shaft and throttle shaft seals.

Not a mere vent hole, but something that looks similar to an elbow fitting, which the factory calls a "breather".

The 55-56 parts book shows it (Plate No. 35) on the LH side of the case (Gr. 3.5062).

Once you know what you're looking for, it can also be seen - more clearly - in Figs. 16, 20, 34, 156, and 161 from the Twin Ultramatic section of the 55-56 shop manual; keep in mind that the case is shown inverted for overhaul.

Check the Twin Ultramatic section of 55-56 installment for this site's Service Index, and you'll find an entry for "Leaks" that point you to related topics that may be of help.

So I cleaned up under the trans and noticed it was leaking from the farthest back acutuator on the passenger side of the car. I tried downloading the manual but it has been 20 min now and still no luck.

What is this actuator and how do I get it to stop leaking. It has a little back and forth play to it.

Thank you for patience with my ignorance and slow computer.

If actuator means a lever connected to a funny shaped rod, the passenger side is the throttle linkage. There is a seal around the shaft which will have to be replaced to stop the leak. A similar but beefier arrangement on the drivers side is the manual shift linkage which also has a seal that can leak.

If the manual finally downloads and you decide to replace the seal, adjustment on the throttle linkage is most important. Follow the book adjustment procedure or make very sure to mark things before disassembly so the lever goes back in exactly the same place on the shaft.

Is the seal a packard only part from kanter or what not or is it like a o-ring seal?

Thanks
Bill

It's just a standard type seal, not a Packard-only part. But unless someone gives you a modern interchange # or you want to take the old one out and get the measurements from it and have our local parts store chase it down, it's probably easier to get it from someone like Pete Fitch (Ultramatic Dynamics), Kanter, or Max.

The Twin Ultramatic section of the 55-56 shop manual (p. 45) confirms this is a lip type seal, not o-ring.

My notes from past discussion show CR #3683 as interchange for OE #421372 (Gr. 3.587). SKF acquired Chicago Rawhide back in 1990, but in more recent years, has been transitioning the CR brand to SKF.

I also show interchange to Victor #48816 and National #340385, but have not verified them.

I used the SKF 3683 from Motion Industries ($5.82 plus s/h 06/04/2013) to replace OE 421372 for the throttle valve lever. I believe that it fits all Ultramatics 1950-1955 (but not 1956).