First Post and question: Manual vs Automatic transmission Fluid as penetrating oil?

[cpileri]

Worthy Sirs and Ma'ams,
This is my first post after reading the forums religiously... and I mean religiously... for a long time. I mostly learn, and didnt have much to contribute. but I finally thought of a question, simple though it might be:

What is the difference in composition btw Manual transmission fluid and (ATF) Automatic transmission fluid? and,

I know mixing ATF w Acetone makes a great penetrating oil. I have a bottle of Amsoil MTF sitting around and am wondering if it would make a good penetrant?

Many thanks and great forum you have here!

C-

[MtGun44]

"Manual transmission fluid"????? Never have heard this term used. Some manual transmissions do
use ATF, but over the many decades when manuals were common in American cars, the standard WAS
what was called "90 weight", now referred to as "80W-90 gear oil". Many foreign trannys now use
a lighter oil for gas mileage improvements. My '89 Accord used 20W-50 engine oil, my 2001 Accord
uses a special Honda only man. transmission oil. My '85 Blazer used ATF in the 5 spd manual, as did
my brother's Mercedes manual tranny.

So - do not worry about using "manual transmission fluid" for a penetrating oil, get a bottle of ATF
and mix up some to try. "90 wt" is very heavy, thick oil - exactly what you do not want for
penetration into tiny cracks, I would think. Great for providing lubrication by slinging around
with gears, but I expect it wouldn't penetrate worth a darn. Never have tried it though.

Two broad categories of ATF - GM and Ford (Dextron versus Type F or Mercon) with lots of other
variations, too. Basically ATF is a very high quality low viscosity lubricant with excellent antifoaming
and anticorrosion properties. Lots of high tech additives to increase lubricity and long stability in
the transmission since they go a very long time between changes. Lots of anti-varnish and
detergent capabilities, too. Fancy stuff.



Bill

[cpileri]

too thick. That was easy. Thanks, Sir!

p.s. yeah, it threw me off too, but it says Manual transmission Fluid right on the bottle.

[Rebel Dave]

I guess it comes down too what kind of vehicle you drive. Mopars take only ATF+4, type fluid in auto trannys. After that
your kind of on your own.

Rebel Dave

[W.R.Buchanan]

ATF is also very high in Detergent content. That's why Auto trans' are so clean on the inside.

Along time ago we would fill an engine with atf and let it idle all day to remove and loosen all sludge before the engine was pulled down for rebuild.

It removed every bit of goo. It would also dissolve every seal in the engine so you couldn't run it for oil.

Penetrating oil works by Capilary action. The thinner the substance the better it flows, however when it does get into the cracks it must then have some lubricity as well.

This is why you just buy a can of Aero Kroil. It is the best! An 8 oz can is about $8 and will last a very long time. It is good for cleaning barrels, and lubricating moulds as well.

Randy

[seagiant]

Hi,
KROIL...the oil that creeps! 10 and 0 baby! 10 and 0!

Mechanics use this to free up brake line fittings because they NEVER come easy!

[firebrick43]

Mtf is a synthetic 30 or 40 weight oil similar to motor oils but typically lack friction modifiers and detergents but have high levels of zinc. Detergents are not wanted because there is no filter to filter out suspendended particals so it better to left them precipitate out and settle in the sump. Also the syncros and wet clutches work better and dont slip with oils that dont have friction modifiers. Most vtwin synthetic 20-50 also lacks these as motor cycle wet clutches can be wrecked with oil containing friction modifiers. The zinc helps with high pressure from the sliding action of the helical cut gears. Mtf has been specified because gear oils hsve been known to attack brass and bronze which the syncros are made of and causes less drag =better mpg as well.
In otherwords atf and mtf dont have much in common.

As far as acetone/atf goes, several studies have shown it to be the best penitrating fluid. I still use kroil just due to the hassle of mixing it?

[ratboy]

i have been doing some experimenting at work and have found a 50/50 mix of acetone and atf works much better at getting rusty stuff apart than anything else i have used. it does not smell as pretty as kroil but it is much cheaper.

[gunguychuck]

There was tests made and a mixture of 50/50 ATF and acetone beat all the commercial products like WD-40, Kroil, liquid wrench and all the others by a very wide margin.

[Jon]

I bought some Kroil the other day at Napa, and it was $15 :shock:
It works great, and my last can lasted almost 2 years but it's pretty expensive.
Then again, how much is not having to drill out a bolt worth?

[Steppenwolf]

Thanks for the heads-up about the 50/50 penetrating oil! Going to whip up a batch.

[Tokarev]

FWIW, ATF should be superior as penetrating oil, as it's designed to operate hydraulics inside the auto tranny, while engine oil and heavy tranny oil are designed to leave thin film on the surface of parts.
ATF with acetone is absolutely superb in penetrating.

[o6Patient]

I've used thinned down atf for a general purpose penetrating/lube for years and it does work well.
ATF is made so it doesn't harm the rubber seals, one of the reasons I like it as a general lube but it
by itself probably doesn't de-varnish well, but the acetone content certainly should do the trick in that
respect.

[saintdel]

Alright! Now I know what to do with those six quarts of ATF I have left over from a long gone leaking dripping oozing Mustang.