Re: Universal oil for automotive use?

There are already some "universal" automotive lubricants and have been
for many years. They are listed as "fleet" use items rather than the
more specific lubes we're used to seeing.

A "fleet" engine oil would be spec'd for gas and diesels and was
generally a 30weight oil, but not is probably some multi-weight variety.
Might not be as good as a OEM spec oil we'd put in our cars, but it'd be
acceptable for a wide-ranging fleet of diverse vehicles. At the present
time, most gasoline car and truck engines will take either 5W-30 or
10W-30 oil, other than those that need 5W-20.

On the automatic transmission side of things, the Dexron spec fluids fit
almost all GM vehicles and pre-UltraDrive Chryslers, plus some
pre-lockup converter Fords. It replaces the old Type A and is backward
compatible in GM automatics back to 1947. It's recently been upgraded
to Dexron III Spec H and then to the new Dexron VI for the new 6-speed

Ford has some different automatic trans fluids too, generally specific
to their vehicles, just as Chrysler has some specific fluids too.
Mercon is generally paired with Dexron III, but the newer Mercon IV spec
is different. I know of one loca trans builder that puts Mercon IV in
the place of Dexron in GM transmissions as it's generally suspected the
Mercon IV is part-synthetic and will take the heat better.

It's also suspected that the new Dexron VI is part-synthetic, but not
firm information on that just yet.

The reason for the newer spec fluids can relate to the way the converter
clutch is used. When we first got them, they were either "ON" or "OFF".
If they slipped, something was wrong, but then they were "analog"
controlled rather than computer modulated. Just as with a slipping
clutch pack in the transmission, a slippling converter clutch (if
modulated to do so by the computer) will generate more heat so a better
fluid spec is needed.

Check out the FAQs for Chrysler transmission fluid recommendations on
the earlier FWD vehicles.

In the case of the Ford and Chrysler specific trans fluids for
particular transmissions, those recommendations need to be followed when
possible. ALL of those fluids are typically much more available in the
aftermarket than when they first surfaced.

In the last couple of years, a "universal" ATF has surfaced from people
like Pennzoil. It meets the various Ford and Chrysler specs, plus
Dexron III. Kind of makes one wonder just how far apart these many
specs were to start with? Or how well these fluids will address the
specificity of earlier Chrysler FWD automatics.

There's TONS of lube information in the manufacturers' websites for
Pennzoil, Mobil, Exxon, Chevron, Castrol, Valvoline, etc. In some
cases, you can even detect a multi-vis fluid aspect of some ATF specs!

In the Mopar Police Car book, it talks about how the CHP maintenance
dept started using 20W motor oil (in the 1960s and later) for engines
and also for automatics. It states that the Torqueflites would tolerate
it with no problems, but that the Ford and GM transmissions did not like
it. Only rule was that after a high-speed pursuit situation, the
vehicle had to come in for a transmission fluid (20W motor oil) change.
In those earlier years, Chryslers had an inline transmission filter with
drain plugs in the trans pan and torque converter, so it was less messty
to do those changes than in later times.

As for the RR use of THM400 transmissions, when they polished the valve
body passages from their rough machined state "as supplied", it did
upset the fluid flow and shift timing from "as designed". I suspect
they could have recalibrated things for the polished passages, but this
got to be one "hands off" area for the RR people--just buy it and
install it without trying to make it better than "as supplied" (which
already met RR's standards for operation smoothness "as supplied" rather
than "as modified by RR" or RR would not have bought it in the first

Chrysler and others have used ATF for manual transmission fluid, rather
than 80W-90 gear lube (i.e., rear axle lube). When Chrysler was doing
it, it was probably as a fuel economy thing as they were highly involved
in the Mobil Fuel Economy runs back then--a "WIN" was a really big deal.
If the trans got noisy, then they'd put the normal gear oil back in it.

GM has used some semi-sythetic and full synthetic manual trans fluids in
recent times. The semi-syn for particular Getrag designed manual
transmission so they'll last to specs and also have good shifting at
lower temps. In other cases, they are regular multi-vis gear lubes.
The Castrol SynTork gear oil is for the heavier duty manual

Now, there are also synthetic rear axle lubes too. Some that reputedly
"eat" or deteriorate silicone rear cover "gaskets" and require a paper
gasket instead.

Yep, more specialized component designs will require more specialized
lubes for durability and also supposedly improved fuel economy. And
this does NOT start to address the specific lubes that imported-brand
vehicles have to have to live a long and productive life.

And you thought needing ATF+3 was a major issue? Get into the import
side of things and things can change really quickly!

ATF and PS Fluid? Different breeds of fluids. Chrysler and GM have
spec'd specific PS fluids for years, since the early 1960s when the
modern style power steering pumps came out (basically). PS fluid is
more waxy, by observation, yet is still basically the same viscosity as
ATF, or a little thicker. PS fluid seems to be of a lower temp
tolerance than ATF also.

Ford spec's Motorcraft ATF for certain Ford ps units. It all depends on
how the systems rubber items and seals are configured. The Chrysler
products I've bought used (1980 is the newest) all had power steering
leaks and "red" fluid in them. When the correct Chrysler ps fluid was
flushed and installed, the leaks stopped and the systems operated

In prior times, it was accepted practice to "top off" a power steering
system with ATF (Type A or Dexron), but if the system has a leak, over a
period of time, the oil will be come more ATF than it was designed
for--hence the observed leaks.

Modern PS fluids are becoming more specialized too. GM even has a
synthetic ps fluid in some vehicles (i.e., some years of recent
Corvettes), probably listed as "Cold Climate" use. Many newer power
rack/pinion steering gear systems are more picky about fluid and
condition thereof, for whatever reason.

Oil might be oil might be oil, but it's not that it's "oil", it's where
it goes and how it's supposed to be used that really matters. ATF and
PS fluid might be similar enough to use ATF in the place of PS fluid,
but it's not the viscosity per se, it's the additive package in the oil
that is the real key. Just as the additive package in the Chrysler-spec
ATF makes it different and not really compatible with any Dexron III
product or Dexron+additive product combination.

By observation, you can short-circuit some oil useages, but in the long
run (maybe the 2nd or 3rd owner time frame), somebody's going to have to
pay for these lubrication indiscretions. And . . . "that dang ________
brand car is a piece of _______" will be the comment, rather than "That
stupid prior owner didn't know how to put the right lube in the

Just some thoughts . . .



Relevant Pages

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