ATF - Where are the detergents

[nicholas]

Hi Everyone,

I have been reading numerous posts about ATF's detergent abilities/ cleaning abilities.
However, when I read various UOA/VOA's the typical cleaners in the additive packs are very low compared to other oils.

Just wondering if there is something I am missing - how do these fluids keep their units clean for 50+k miles?

 

[67lemans]

One reason they are so clean is the fact there is no combustion taking place in your trans.

 

[G-MAN]

An automatic transmission is essentially a closed unit. The oil in it is not subject to contamination from combustion as happens with engine oil. Hence, there is very little need for any detergents in ATF.

ATF's useful life is limited by oxidation and the depletion of its VI improvers and friction modifiers, not from dirt and contamination.

 

[440Magnum]

Originally Posted By: nicholas
Hi Everyone,

I have been reading numerous posts about ATF's detergent abilities/ cleaning abilities.
However, when I read various UOA/VOA's the typical cleaners in the additive packs are very low compared to other oils.

Just wondering if there is something I am missing - how do these fluids keep their units clean for 50+k miles?



ATFs do not need detergents, just good particle dispersants to keep the clutch wear dust in suspension. There are no combustion gasses contaminating ATF to create all the nasties that detergents are there to control. And unless the unit is SEVERELY overheated, there's not even the same amount of oil oxidation going on in an AT that there is in an engine. An AT is a pretty surgically-clean place, except for the clutch dust.

 

[RF Overlord]

Originally Posted By: 67lemans
there is no combustion taking place in your trans.
I bet "Oil Changer" will disagree...

 

[NHGUY]

And yet wives tales claim a quart of ATF in the oil will clean up a dirty engine....without detergents?

 

[MolaKule]

Actually, ATF's still contain about 120ppm of detergents, but the dispersants are non-metallic organics. The detergents are 1/15th to 1/20th the levels in engine oils.

You need detergents to reduce or remove varnish and any oxidation products that may form.

Varnish is problematic because it can glaze clutch packs and cause the valving in the valve body to stick.

 

[nicholas]

Thanks guys -