Transmission Fluid Facts

[Dave]

I posted this on W-body, thought I'd help everyone out by posting it here too...


okay, I am looking at my old textbook from school - "Automotive Technology - A Systems Approach - 3rd Edition"

I'd like to put a few quotes in here from pages 988, and 989

"The various chemicals added to ATF ensure its durability and overall performance. Zinc, phosphorus, and sulfur are commonly added to reduce friction [friction modifiers]. Detergent additives are added to ATF to help keep the transmission pars clean. Dispersants that keep contaminants suspended in the fluid so they can be trapped by the filter are also added.

Because some chemicals used in the composition of transmission fluid may adversely react with the fibers or synthetic materials used in the seals of the transmission, the compatibility can result in external and internal transmission fluid leaks due to deterioration, swelling and/or shrinking of the seals."

"To reduce ware and friction inside a transmission the most commonly used transmission fluids are mixed with friction modifiers. Fluid types A, CJ, H, Dextron, and Mercon have friction modifiers [reduce friction] added to the ATF. Transmission fluids with these additives allow for the use of lower clutch and band application pressures, which, in turn, provide for a very smooth feeling shift. Transmission fluids without a friction modifier, such as type F and G tend to have a firmer shift because higher clutch and band application pressures are required to avoid excessive slippage during gear changes.

If an ATF without friction modifiers [type F] is used in a transmission designed for friction modified fluid [Dextron III] the service life of the transmission is not normally affected. However, firmer shifting will result and the driver might not welcome this change in shifting quality. Transmission durability is effected by using friction modified fluid in a transmission designed for nonmodified fluids. This incorrect use of fluid will cause slippage, primarily when the vehicle is working under a load. Any amount of slippage can cause the clutches and bands to ware prematurely. Also, because of the high heat generated by the slippage, the fluid may overhead and lose some of it's lubrication and cooling qualities, which could cause the entire transmission to fail."

I hope this helps people a little (sticky maybe?)

--Dave

[bszopi]

I may copy that to the website and put a note about it in the sticky that we already have. Very interesting info. Thanks for sharing!

[bud36light]

Last time I installed a Turbo 350 B&M shift kit I actually read the directions and lo and behold it said to add so many quarts of type F! WTF I thought. This goes against what I learned over the years. I called B&M and got basically the same story as Dave gives. I HAVE NOT (yet) tried type F in the 4t60E But I am thinking about it. It damn sure held up in that 350. Did alot of towing my camper(30 foot), slinging mud in places I shouldnt have been and generally pulling and haulling all of my friends stuff all over. This trans was abused and beyond and it lived. Also gave FIRM shifts. Kevin

[Dave]

I was running type F in my 88 Regal 4T60 (non-E) for 2 years still had type F when I sold it 2 weeks ago, running very well.

When I change the trans fluid in my Z34 (4T60-E) I'm gonna use type F.

--Dave

[bud36light]

Hmmmmm.......

[v6h.o.]

i still have that same text book from when i went to school for automotive apprenticeship.

it is some good info

[4spdz34]

i used type f in my z34

[Lyle's GTP]

Yes........and how does it shift?

Lyle

[4spdz34]

well mine wasn't stock at all. 3.73 gears, 3k stall, valve body shift kit and custom kit for the accumulators, with adjustable vaccuum modulator. it would get rubber in between gears at 7100 rpm

[Lyle's GTP]

Nice

Lyle