Trans Fluid Facts (not looking for a fight)

[DaveFromColorado]

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

[THe_DeTAiL3R]

Thats some good reading.

 

I've been reading stuff over on the Ontario/Quebec GP board, which are mostly L67 GTPs, which hard on their transmissions. Heres some stuff about synthetics vs. ATF

 

Since you have to be a member to view the forum, I'll just quote some stuff.

 

If you want to sign up and read the thread.. http://www.oqcgp.com/forum/viewtopic.php?t=6439&postdays=0&postorder=asc&start=15

 

Thief Garrett wrote:

Buy your self some Mobil 1 ATF and a filter kit at CT, cost you around $100. Ofcourse there are cheaper fluids, about half the price, depends on you I think they're not bad...

 

Actually the jury is still out on that one. There have been numerous debates pro and con synthetic ATF in our cars. I use just regular Dexron II and change it every year. Apparently synthetic ATF is too slippery for our trannies.

 

Thief Garrett wrote:

I told myself that from now on I'm gonna change my trans fluid every 25K km. since I do WOT often at hwys. and drive the car a bit hard. By the way I'm on my 2nd transmission and the first one failed at 120K km. (it was too young to die).

 

Good decision, I change my ATF every spring as well

 

I've had both and the car pulls so much better with the standard ATF. Besides, if someone is going to change the oil and filter on a yearly basis, its a waste of money to pay for the extra cost of synthetics in the tranny (unlike the engine, where all I use is synthetics). There is also a lot of talk about decreasing clutch life due to the extra "slipping" that synthetics offer as well.

 

I'm not sure about the good vs. bad points, all I know is that I had synthetics in my tranny for 2 years, went back to standard ATF and the difference was positive enough that I am doing the yearly changes with standard ATF from now on.

 

My personal experiences aside and the experiences of others that have done this as well, GM doesn't put synthetic in there, and there is a thread on clubGP if you have the patience to search for it, where they discuss this pretty thoroughly... flaming asside... lol.

 

I lost about 2 tenths with synthetic tranny fluid and got it back the day I switched back. If you do yearly fluid exchanges, there is no reason to slow yourself down (IMHO) and shorten clutch life due to added viscosity.

 

Does it feel good? Sure does, makes the car smoother, the shifts imperceptible... but smooth = slipping = more clutch wear = slower accelleration times at the 1/4 mile.

 

If someone wants to try it and has the time/funds to waste, go ahead and give it a shot. This is not something that will grenade your tranny tomorrow if you do it.

 

Heres another link: http://24.37.28.93:9000/maintenance.htm

[THe_DeTAiL3R]

Another question - the type F looks interesting to me.. would it be bad to mix with Dex III?

[DaveFromColorado]

where as I didn't find any information about mixing F with Dex3 I've done this myself, and haven't had any problems with it, but I can't quote any actual source at this time.

 

--Dave.

[mihela816]

I use regular B&M trick shift and it works well.

[Justin]

I don't know if I'd actually mix it, but I run Type F in my Ventura, swapped it over after I grenaded a sprag clutch and ring while racing a mustang. I'd try to get as much type f into your trans as possible, maybe flush it twice even.

[DaveFromColorado]

bump

 

make this info fresh to the newest members....

 

--Dave