1955 Dynaflow Leak - How much is normal?

[EconoJoe]

So I'm knee deep sorting out an ever growing assortment of mechanical and a few appearance concerns on a 55 Super that I bought about 6 weeks ago. After reading a number of posts about notorious Dynaflow leaks it came as no surprise that mine has a few external drips and, when I checked the differential oil level, I was greeted with about a cup or so of ATF flowing out. The good news is that it seemingly hasn't pumped enough back to effect the rear axle seals, as the inside of the backing plates are dry.

 

I've been noticing a lot of "they all leak" posts. So the question is how much is too much? Clearly the external drips are just a matter of personal tolerance and keeping it filled. What I'm trying to figure out if that amount of ATF dilution into the rear axle lube is a huge deal, a concern, or nothing to loose sleep over. This is all along the lines of deciding if I should go after replacing the torque ball & output shaft seals or not.

[old-tank]

They do not all leak.  All leaks   should be addressed especially if leaking down the torque tube into the rear end.  This will destroy your rear gears.  Buy and install an outer torque ball retainer kit.  Link to discussion.  Your service manual will be your guide.

 

[EconoJoe]

OK. I'm going all in on this car anyway so why not jump in on this. My follow-up question is to ask if there is much difference between the kits that I see from various vendors? And are there any potential 'extras' beyond the average kit contents that I might find needed in there once it's apart?

[old-tank]

Get a kit from http://www.autotran.us.  This has all you need.

If you get one from a different vendor  send it back if the retainer is silvery plated; those have a high incidence of reports of failure..

[60FlatTop]

Here I thought GM designed crankshaft and transmission seals to leak so they wouldn't be all dry and flaky like the Fords.

 

Used to see a lot of guys replacing rust Ford oil pans, don't remember any GM's rusting out.

 

And Hudson's made them so the clutch would sling it out all over the place.

Edited April 23, 2022 by 60FlatTop (see edit history)