Anybody use Sythentic Tranny Fluid

I live in a Toronto suburb, and have no garage or carport. I have a '97
Intrepid with the 3.5 engine.

As suggested my most auto mechanics and writers, I don't let my car warm up
for long periods during the winter - only long enough to brush the snow off
my car. If there is no snow, I usually let it idle for less than 30 seconds,
and drive slowly for the first couple of blocks.

I don't have a problem with the engine working when cold, but the tranny
seems to shift roughly until it gets warmed up. I have had occasional rough
shifting in warm weather too, but its a constant in the cold.

The tranny is a rebuilt with about 50K kilometers(about 34K or so miles) -
not new, but not old either.

I was thinking of getting my tranny fluid flushed and putting synthetic
tranny oil in to help in the cold. I could use the block heater as well, but
not sure if the heat would get to the tranny.

Any suggestions?

James Linn

 

Be safe and stay with Mopar ATF+4. Designed for the transmission.

 

The point is that one MUST use the fluid recommended by the manufacturer.
The DC 4-speed tranny is an electronically controlled unit that is
calibrated for fluid with certain characteristics. Using another fluid, even
if "superior" by some criteria, will reduce performance and may well damage
the transmission.

 

That transmission needs ATF+3 or ATF+4 and NOTHING else. The only
synthetic tranny fluids I know of are Dexron/Mercon (and they really
aren't much more synthetic than any other ATF- read the label and it
says 'synthetic EXCLUSIVE of carrier oil'). If you think it has problems
now, wait until it gets a dose of the wrong-spec fluid in it!

The shift schedule is altered by the computer when the engine is cold
and it does feel different- does your engine ever fully warm up? IF not,
get a new thermostat. If it does warm up, does the COMPUTER think its
warmed up? The computer gets its engine temp info from a different
sending unit than the one that drives the dashboard guage, so make sure
that the computer doesn't have a code stored indicating that the engine
never reaches operating temperature.

 

Fluid flushing can make a difference, as well as resetting the TCM to
put it thru a re-learn (there's a fuse you pull for a few minutes to
accomplish that). You might also consider having the dealer re-flash
the TCM with the latest firmware (have them check to see if you have the
latest rev.) - but that will typically cost you $50 to $125 depending on
the dealer (might want to try the fluid and re-learn first).

I know my '99 Concorde had cold shift problems when I first got it at
58k miles. I changed the fluid and filter, and at the same time had the
TCM re-flashed (which I assume automatically put it thru a re-learn
cycle too, but not sure about that) - there had been a revision in the
firmware. Can't say for sure which did the trick, but the problem was
fixed by one or a combination.

Re: synthetic, I agree with the advice to stick with ATF+4, but I can
tell you that the president of the 300M ezBoard uses Amsoil ATF in his
300M (same tranny) and has no problems (don't shoot me - I'm just the
messenger - I have no horse in that race - the question was asked, I
answered it). 8^)

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

 

James

Look at AMSOIL ATF. It meets the specifications of Chrysler ATF+4

www.thebestsyntheticoil.com/atf.htm

Bruce

 

Good idea. If you have the original ATF+3 in there then replace it with
Chrysler ATF+4.

Chrysler ATF+4 ___IS_SYNTHETIC!!!___ Look up the specs!

Ted

 

Chances are Chrysler won't warranty the trans if you don't use MOPAR
ATF+4.

Your link only states that it's "recommended". Has not been approved
for warranty apps by Chrysler.

More expensive than MOPAR ATF+4 by 30%.

 

Dave brings up a good point. There is something called "cup volumes",
which if I understand it correctly, is the volume of fluid that it takes
to fully throw a given mechnical actuator inside the tranny, and thus
determines the duty cycle pulsing that the TCM needs to deliver to the
solenoid controling that actuator to shift the tranny smoothly. IOW, if
a given cup volume is more that the TCM thinks it is, the shifting will
be sluggish and inefficient; if the volume lower is lower than the TCM
thinks it is, the shifting will be harsh.

Whether that makes sense to you or not, the fallout of all that is that
*if* you do change the type of fluid, you should have the dealer re-set
the TCM so that it re-calibrates itself to the actual cup volumes with
the properties of the actual fluid that is in there (right after the
fluid is changed). I don't know if that can be accomplished with a
simple TCM re-learn process (in which case you could do it yourself by
pulling a certain fuse for a few minutes), or if it can only be done by
the dealer with special equipment.

Would you agree, Dave, that if the fluid is acceptable in all other
regards, if the TCM is recalibrated to that fluid for the cup volumes,
all should be fine?

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