1958buickforum.net

Here is some info posted in 2004 by Bill Schoening. Does anyone have updated information? It seems that the oil companies reformulate and lower the zinc levels in oil and tranny fluid every few years:

I will pass some info that was given to me on Trans fluid. Type A is no
more. You can use Dexron III, However Dexron III has been formulated to
work in new transmissions. The older (Dynaflows etc) have more metal to
metal surfaces where heat can be a problem. The older trans fluids
contained special additives for good heat transfer, one of those is
zinc. This has been removed. One person who specializes in racing with
older transmissions is using Type F fluid. Type F still contains the zinc
and works better for the heat transfer problems. This is still
available. I have been using Type F in older 350s 400s with no problems. I
have added some type F to my Flite pitch and seems to run
better. Unfortunately I rebuilt and filled the trans (3gal), with Dexron
III before I had this info. When I drain it and refill it I will be
switching to the Type F. I drive my 58s here in Arizona and If there was
to be any heat problems we would have them.

In a regular Dynaflow I would not expect to see any problems using Dexron
III. In the Flite pitch so far no problems, but there is more heat
generated in this transmission. Over time and miles there may be more wear
on the parts from the heat. This is a problem as repair parts are hard to
find. So any thing you can do to reduce the heat the better on the Flite
Pitch. If you are a BCA member I talked about this in an article I did in
the Bugle on the Flite Pitch transmission several months ago (April 2003).

Thanks for the info, Bill.

Thanks for the info. How do I know if I have a regular Dynaflow or a Flight Pitch transmission in my '58 Special? Or does it really matter and I can just use the Type F fluid?

The flight pitch dynaflow was optional. It has a square pan on the bottom. The variable pitch dynaflow has a rectangular pan. Also, the shift indicators are different: PNDLR for variable pitch, PRNDG for Flight Pitch. Type F should be fine in either.

I currently use type FA in my Flight Pitch and seems to work just fine.