Wrong Transmission Fluid

I understand that Dexron transmission fluid is not to be used in Chrysler
front-wheel drive transmissions, and that the correct fluid to use is ATF+4.
I¹ve also heard that wear and damage can result from using the wrong fluid.

My ¹98 Town & Country transmission was recently overhauled by a local
transmission shop. About 200 miles later, the trans started having trouble
shifting and was slipping badly. Rather than take it back to the same shop,
I took it to the local Chrysler dealer. They took it apart and showed me
the disassembled transmission. It appeared that the original shop did
rebuild it correctly, replacing the clutches and gears. But the clutches
were badly burnt and had to be replaced again. It was then that I found out
that the original shop used a Dexron/Mercon fluid instead of ATF+4.

My question is: Could using the wrong fluid have caused the clutches to
burn out so quickly? I don¹t see any other explanation. Wouldn¹t this be
considered negligence or incompetence on the part of the people who used the
wrong fluid?

Also: What is it about Dexron that causes damage to Chrysler transmissions?

[To reply by email, replace the last letter of the alphabet in my email
address with the letter "p"]

 

Absolutely the Dexron could be responsible for the damaged clutches.
The earlier Chrysler TSB's that OK'd changing over older vehicles that
came with earlier types of ATF to ATF+4 excluded certain vehicles from
the approved changeover list. The reason for the exclusion of those
vehicles specifically cited potential for damage to the clutches.

NOW - a later TSB superceded that one and added in those previously
excluded vehicles (which I believe were certain years of the minivans).
I'm not a transmission expert, but the fact that there was caution and
delay in approving the preciously excluded vehicles tells you that the
fluid properties are critical to preventing clutch wear/damage. But I
don't know how you prove it.

The transmission service industry is convinced that Dexron™ with an
additive is equivalent to ATF+4, and uses the circular argument of their
own trade journals to "prove" it.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I very much doubt it. The trans shops that substitute the cheaper Dexron
use a "shift improver" fluid (Lubegard is a popular one) that changes the
sliperiness of Dexron to make it match ATF +4, I'm sure that yours did
too. But even if they didn't, 200 miles is way too short.

A number of years ago I bought a 1995 T&C that had 20,000 miles on
a rebuilt transmission. Being the suspicious type as soon as I got it I
looked
up the specs and read about the transmission fluid issue. I then called the
rebuilder and asked them what fluid they used - Dexron, of course. Needless
to say I changed the fluid out. The van is still running fine.

I think that the simple answer is that the shop that did the rebuild simply
didn't put the transmission back together again properly.

I think that is immaterial. After only 200 miles you have a warranty claim
and
I would pursue it. If you paid for the rebuild with a credit card I would
call
the card company and get the charge disputed. With a signed statement from
the Chrysler dealership that the rebuild was done wrong, you have a pretty
open and shut case from the credit card company's point of view. If the
shop that did the rebuild is stupid enough to come after you, you can sue
them
for fraud pretty easily.

I would avoid getting involved in telling the shop that did the rebuild what
the problem was. Your not a trans expert, your word is meaningless. What
you need to do is call the rebuild shop and explain what happened and
tell them you want a refund. If you don't have the credit card dispute
mechanism you may have to settle for a negotiated refund if they did in
fact replace gears or other hard parts - since those parts were not damaged.
If they want to call the dealership and get the story from the dealership as
to
what was done wrong, that is their business.

There's been a number of theories but I have never seen a scientific
analysis
even by Chrysler so I take the theories with a grain of salt. What is
strange
is it would be rediculously easy to setup a test rack, and put a fresh trans
in it, instrument the hell out of it, then fill it with Dexron, then run it
until it died.
Then we would have definitive proof as to what it was.

The theory I've read that seems the most reasonable is that the trans
computer
is programmed for a certain "slipperyness" of the fluid, and Dexron is too
far
off spec, as a result the computer thinks the clutches haven't engaged when
in fact they have, so it attempts to reengage the clutches multiple times,
this
wears them out quicker. But this smells like a theory generated by someone
sitting in a chair and guessing, it does not sound like an actual
description
of an instrumented trans in a test rack with Dexron in it.

Personally, my gut feeling is that the longevity of these transmissions when
run with Dexron + shift modifier fluid is much, much, much closer to that
of ATF +4 than Chrysler is comfortable with. I think if the failure was
spectacular and rapid, Chrysler would have by now created a video or
some such to show the difference and the Internet would abound with
stories of people putting the wrong fluid in and blowing their
transmissions.
Instead, Chrysler seems content to allow the transmission repair people
to dream up speculations as to what the real issue is.

Naturally, this is not an endorsement of Dexron in these transmissions.
But the plain fact is that if it was well proven that using Dexron would
shorten the life of these transmissions by only, say 15%, then a great
many people who I'd classify as "bottom feeders" would use Dexron
to save a few bucks.

Ted

 

To do it right, multiple units would have to be simultaneously tested
along with identical units of the same lot filled with the correct fluid
- ATF+4 as a control. The cost of the experiment just went up. But
no-one has the incentive to make the investment since only the consumer
is getting screwed regardless of the truth of the matter.

Funny - you never hear of Consumer's Union doing this kind of telling
testing, when it seems that it fits exactly in their charter. Why is
that? Must not be any money in it for them either.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

Because the average consumer has no understanding of what real
product testing is all about, and so does not demand better than the
schlocky testing that Consumers Union and also Consumer Reports
does?

Ted

 

It's possible. Dexron would most likely only directly damage the torque
convertor clutch, but when the TC clutch lets go it sends fluff all
through the rest of the transmission and that could have blocked the
filter and caused low pressure, which could have then burned out the
rest of the clutches.

But that's just a hypothesis, it could have been any number of things.

It has the wrong differential between its static and dynamic coefficient
of friction. In other words, a clutch lubricated with Dexron III will
slip easily, but then grab when it stops slipping. ATF +4 has a much
smoother transition between sliding and sticking because the static
(stuck) coefficient of friction is much closer to the dynamic (slipping)
coefficient of friction. The torque convertor clutch in Chrysler
electronic automatics (and now virtually all other manufacturers, but
Chrysler was the first to use this system in 1989) is designed to be
used in a partial-lock mode, where its engaged but deliberately
slipping. This is done in 2nd, 3rd, and 4th gears (now 5th and 6th too
on newer transmissions) to improve fuel efficiency by reducing fluid
coupling the losses in the convertor at the high end of each gear. But
when the clutch is being deliberately slipped like that, Dexron III
fluid will cause it to "grab" over and over causing a noticeable
shudder. That will also begin to break the friction material off the TC
clutch, and then it contaminates everything else or plugs the filter.
When the filter plugs, fluid pressure drops and the servos can't keep
the other clutches firmly enough engaged, so they slip and burn out.

 

I've seen that kind of clutch burn out if the shop failed to soak the new
clutch in AFT before they were installed. If the clutches were put in the
transmission dry, they won't last more that a few hundred miles. The use of
Dexron will make it shift horribly but I doubt that the use of Dexron would
"burn" the clutchs that fast. Either way, the shop is at fault. Not much
of a transmission shop if they don't know to use ATF+4.

 

I bet if you surveyed the local tranny shops where you are, better than
90% would tell you they would use Dexron with an additive vs. ATF+4.
The aftermarket service world is eat up with bad information.

I called four shops in my area (two of which were highly recommended by
everybody and their brother) and asked them what fluid they would use in
my 2nd gen LH car, and all four said they'd use Dexron with additive. I
changed the fluid myself.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

The last time I had an electronic Chrysler transmission rebuilt, I
bought and carried in 3 gallons of ATF +4 and said "humor me- use this."
And they did.

 

This seems to be fairly common. I had the transmission in my 1993
Voyager rebuilt last August. When I went to pick it up, I ask the shop
owner what they filled the transmission with. He said that he used
dexron with Lube Guard. When I expressed my concerns, he pulled the
empty bottle out of the garbage, and showed me where it says that it
meets Chrysler's requirements. The shop has been in business for many
years, and does warranty work for several dealers.

Anyway, the transmission is working fine so far. The Automatic
Transmissions Rebuilder's Association warranty runs out in August. At
that time, I will probably replace the fuild myself and use ATF+4,
just for my own peace of mind. Chrysler labeled ATF+4 can be bought at
Walmart for about $4.50 per quart.

I can understand why shops do not want to stock every kind of fluid
that is required by each manufacturer. At the same time, the
transmission fluid issue has been covered extensively in this NG. The
general opinon has been to use the recommend fluid, which is now ATF
+4.

On another note, in my van's early days, I used to take it to the
local Chrysler / Plymouth dealer for transmission service. Each time,
they would replace the fluid with ATF+3 (that's what was available at
the time) along with a "conditioner." When asked them about the
conditioner, they said that it was to ensure that new fluid would mix
okay with the older fluid. When I mentioned that Chrysler does not
recommend any additives, he stood by his position.

I still don't know what the additive was, or who made it. I tend it
was a way for them to make a few extra dollars.

-KM

 

Chrysler's requirements for which fluid? There are several Chrysler
fluids. You can't simultaneously meet the requirements for all of them.
The aftermarket manufacturers know this but are very dishonest in
their labeling, and the shop owners are willing to play along them for
their benefit, not the vehicle owners, *knowing* that the label is
misleading. They are dishonestly inpolying that if it's printed on a
label, it must be true in every possible context. The shop would be
hard pressed to find in print anywhere in their literature that it
specifically met the requirements of ATF+4 in a way that could stand up
to a court challenge.

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

....implying...

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my
address with the letter 'x')

 

I believe that the Chrysler specification for ATF+4 is MS 9602, while the spec for
ATF+3 is 7176. I don't think it is possible to meet both specifications
simultaneously, although ATF+4 should now be ok for transmissions previously built
for ATF+3, per Chrysler service bulletins. (Those MS numbers are from memory, so I
may be off). I believe MS stands for Mopar Specification or similar.

That assumes that a bottle labeled as meeting spec xyz actually does meet it.

 

Material Specification

 

Heh, the memory fades.....Material Standard.

 

local Chrysler parts dept tells me you can run ATF+4 in an older ATF+3 trans
but once you put it in, you cant go back to +3

don't know how legit that is but I don't want to risk it myself, and since
ATF+4 is now available at Wally world, I'll stick with it since I started
using it.

 

Nonsense. Although there's an enormous amount of effort by
Chrysler to mystify this fluid, the frictional coefficient between
ATF+3 and ATF+4 is the same. The only difference is that
ATF+4 is synthetic oil, ATF+3 isn't. ATF+4 lasts longer in
the transmission before breaking down, because of this.

Ted

 

My dealer has been putting ATF+4 in my '95 Chrysler for years.

 

Which is a VERY good thing. ATF +3 was HORRIBLE fluid when it came to
oxidation rate and other degenerative processes. Both Dexron III and
Mercon V were vastly superior in longevity, but of course simply
wouldn't work right in a Chrysler automatic because they had the wrong
friction properties. ATF +4 fixed the degenerative properties of ATF +3
wile maintaining the right frictional properties.

 

I don't believe this because after ATF +4 was introduced Chrysler did not
vastly increase the servicing interval for use of ATF +4 vs ATF +3 in these
transmissions. I think your being misled.

ATF+3 was manufactured by other people than Chrysler. However,
with ATF+4 Chrysler has control of the additive package, and no matter
where ATF+4 is sold, and by whom, Chrysler gets a cut of it.

Ted