Hydramatic fluid change

[Summershandy]

I'd like to drain the trans fluid this spring through the drain plug. I know the '54 likes type A fluid and Mercon/Dextron III/IV is acceptable. I believe the entire fluid doesn't drain from the entire trans so my question is, I don't remember what type of A fluid I originally used so will any of these fluids be compatible with what may be left over in the trans? 

[EmTee]

If you have Type A, Dexron, Dexron II or Dexron III (or a mixture of these) in the transmission now, then new Dexron III/Mercon fluid will work fine.  I have been using Valvoline in my cars.

 

 

Do the drain/refill two or three time after driving awhile if you want to refresh all of the fluid in circulation (including torque converter).

[Bloo]

The catch is that they apparently can't call it Dexron II or III anymore because the standard is deprecated. You'll have to read the small print on the back of the bottle to see which one it is.

 

 

[EmTee]

If they kept the 'recipe' and just updated the name on the label, the formula should be equivalent to Dexron III.  When it was first released, Dexron III was claimed to be backward compatible all the way to Type A.

[PONTIAC1953]

the fluid coupling has a drain plug of it's own, I recommend draining the case and the coupling, getting a new pan gasket so the pan can be removed to clean out sediments if any in the pan, and to remove, clean out, and blow dry the tran's screened fluid filter, put it all back together, pour in 7-8 quarts, start engine, let it idle, add more till you have poured in 10 quarts, then as you slowly add the 11th quart, keep checking the fluid level and STOP when the stick reads FULL, DO NOT OVERFILL just because some of the 11th quart is leftover. with engine still running, move the gear selector slowly from Neutral to reverse and back several times, check fluid level once more.

[Summershandy]

I read your procedure and thought, "filter?" I had to go back to my original pictures when I did replace the fluid to see. It seems like so long ago that I had totally forgot about a filter. It didn't look too bad and there was sediment in the pan. Maybe I'll give it a total change out this summer. I see in the manual some drain torus cover plugs are located inside the flywheel. Would mine be as in the picture?