Paul,
ATF is just very light oil, very similar to 5606 hydraulic fluid. It
contains friction modifiers to prevent clutch chatter. The different
varieties of ATF mostly has to do with what type of friction modifiers are
used. Some manual transmissions are now using Dextron III ATF for gear oil.
It provides lubrication with much lower drag than heavy gear oil but
requires a different friction on the syncro's to work well.
AFT is also the trick fluid for starting a fuel flooded rotary. One squirt
of ATF to lube the seals and they fire right up.
Synthetics are available, the ford mercron V is synthetic. Several other oil
manufactures also sell synthetic ATF.
Larry
So maybe it has detergent to free the stuck apex seals?
--
Paul Lamar ...No rotor no motor.
ATF has detergents and dispersants in the mix. Auto transmissions are
basically hydraulic systems. Fluids have to separate and air water quickly
and protect yellow metals from corrosion, control acids, stay clean and in
grade, and maintain proper friction properties.
OEMs prefer to stay with lower grade (cheap) petroleum fluids when they can,
but smaller fluid capacities and hotter running transmissions are forcing
higher quality fluids. (For example - Dexron III forced more Group II use
in late 2002
http://www.imakenews.com/lng/e_article000097887.cfm ... And
Dexron VI nad to be stronger yet two years later:
http://www.imakenews.com/lng/e_article000384801.cfm?x=b11,0,w )
75W-90 gear lube has a viscosity of about 15 centistokes (cSt) (SAE 40
engine oil). GM/Chrysler synchromesh (and SAE 30 engine oil) is about 10
cSt. Honda CVT fluid is about 8. Dexron II/III/Mercon is about 7. Some of
the latest VW manual transmission fluids test at 6.3 cSt. Mercon SP ATF is
about 6 cSt. (5.6 - 9.3 is SAE 20 engine oil).
Mobil 1, Redline, and AMSOIL make PAO and/or ester fluids, as do Euro
companies like Motul, Elf, Lubromoly, etc. Castrol 'TransSynd' is a Group
III 'synthetic' used in Allison light and medium duty transmissions. There
are other Group III ATFs, and synthetic blends. (Group III is dewaxed and
hydrocracked petroleum that can be called 'synthetic' in North America.
It's not accepted as synthetic in the rest of the world.) US synthetic
blends are often Group III with petroleum. Euro synthetic blends are
normally PAO &/or ester blended with Group III.
Andy
Thanks Andy....
And if you can read that in one breath......
The high detergent makes sense, as we have also used ATF in piston engines
to clean sticky hydraulic lifters. Just replace half the oil with ATF, drive
for a day, drain and replace with fresh oil. No more tick... tick.... tick!
Larry
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