1941 olds hydromatic transmission

[dbm350]

I am helping my dad with some maintenance on his 41 Olds.  We need to know what type of automatic transmission fluid to use. Does anybody know or have experience with these hydromatic transmissions? Any help appreciated.

                                                                                                                           Thanks

[Frank DuVal]

AFAIK, Type A, which is now replaced by Dexron/Mercron. It probably said 10 w turbine  oil in the shop manual. This is based on what the Hydromatic used in the early 50's.

[Spinneyhill]

MoToR's Manual says it should be Hydra-matic oil! For a temporary fill, it says any good grade of 20W oil is OK but should be replaced ASAP. If the oil pan has been removed and cleaned, it takes 9.5 quarts. If the trans. has been disassembled, 10 quarts.

 

Here is the same question on the H.A.M.B.  https://www.jalopyjournal.com/forum/threads/what-oil-in-a-hydramatic.391140/

 

Another AACA thread on this topic. 

 

 

 

[dbm350]

Thanks for the replies. Looks like Dexron will work.           Thanks

[Pfeil]

One of the interesting ingredients of the old type "A" Hydra-Matic fluid was whale oil. I would like to see how a Hydra-Matic gets on using CVT automatic trans fluid, one of it's secret ingredients is whale oil too.

[Spinneyhill]

Wikipedia has this sentence in its article on Automatic Transmission Fluid:

"It turns out that Type A was basically a nearly 50/50 mix of Type F (Ford) and Dexron (GM),^{[citation needed]} "

[61polara]

On ‎9‎/‎29‎/‎2018 at 5:47 AM, Spinneyhill said:

Wikipedia has this sentence in its article on Automatic Transmission Fluid:

"It turns out that Type A was basically a nearly 50/50 mix of Type F (Ford) and Dexron (GM),^{[citation needed]} "

If it's on the internet, it has to be true.  Since Type A was around before Dexron, I doubt that it was a 50/50 mix of Type F and Dexron.

[Spinneyhill]

45 minutes ago, 61polara said:

If it's on the internet, it has to be true.

Yeah, right. I was hoping someone in the know would tell it like it was.

[Pfeil]

In the 1950s, 1960s, and 1970s, ATF contained whale oil as a Friction modifier. But since whale oil would break down at higher temperatures, cars produced in the 1970s and later would not be able to use whale oil because of the higher engine coolant temperatures employed to reduce emissions and save fuel. A moratorium on whale oil at that time prevented the continued production of older ATF such as the original DEXRON formulation (Type B), and the Type A which preceded it. Vintage Chrysler products (Dodge, Plymouth, etc.) used Type A fluid, which is generally difficult to obtain now. It turns out that Type A was basically a nearly 50/50 mix of Type F (Ford) and Dexron (GM), so if you have a pre-1990 Chrysler vehicle, you can mix Type F and Dexron to get a near-match for type A. General Motors began marketing Dexron II Type C and later Dexron II Type D to replace the fluids which were made from whale oil.

 

Edited October 4, 2018 by Pfeil (see edit history)

[Dan Griffin]

Use type A in the old hydros.The old hydros do not run hot.

[John_Mereness]

80K miles in 41 Cadillac w/automatic with the good old fashioned Dextron red color type A.  And always when changing added a can of Trans X Automatic transmission Stop Leak Fluid - helps with the leather seals.

Edited November 14, 2018 by John_Mereness (see edit history)