41TE sometimes does not engage

I have a late '90s Voyager on which the transmission sometimes does
not engage. This happens shortly after starting and always just as one
slows down for a junction and then tries to accelerate again to speed up.
The engine spins quickly, but the transmission does not engage, so no
power is transmitted and the vehicle does not accelerate. After a couple
of times of releasing and depressing the accelerator pedal, the
transmission will smoothly engage and the vehicle will proceed normally.

Does anyone have any suggestions on what might be happening?

The transmission has about 50k miles on it since a rebuild at 95k miles. I
have been careful to change the transmission fluid every 15k miles since
the rebuild, using approved fluid (although I have moved to the
semi-synthetic fluid now, which is claimed to be compatible with this
transmission).

 

I went through a similar problem with my 1993 Voyager. It had an
intermittent electrical problem where the solenoids were not getting
power when they should. The shop cleaned and re-fitted every
connector. It has now been four days and 82 miles without a problem.

When this tranmission has an electical failure, it will go into "limp"
mode, or 2nd gear. That is most likely what you are noticing.

I would suggest taking it to a competent shop that has the proper scan
tool for diagnosis. The fault codes read from the transmission control
module should give an indication of why it went into limp mode.

-KM

 

Well, the shop found codes indicated that the box had overheated, and that
the temperature sensor had failed (due to the excessive temperatures) and
some other issues. They suggest that a snap ring had warped and fallen off
the clutch shaft.

Why is it that Chrysler cannot get enough cooling in these tranmissions
for anything other than flat roads?

 

Good question. I had always understood that a tranmission cooler was
not necessary except for pulling trailers, or under heavy load
conditions.

Your experience seems to indicate otherwise.

-KM

 

A minivan is not very "mini" any longer. Minivans since the late 90s are
a pretty big and heavy chunks to drag through the wind, and are at least
as hard on a transmission as a more aerodynamic car pulling a small trailer.

Also, the early electronic transaxles like the 41TE run full hydraulic
line pressure all the time and generate more heat as a result than older
all-hydraulic transmissions (eg 904 and 727) that vary the line pressure
depending on throttle position.

 

Yes, but I believe that the designers at Chrysler may know about this.
It's clearly a design problem.

Question: because the brakes are also under-specced on this vehicle (I've
had them fade out several times), I sometimes shift down to use engine
braking -- could this result in excess transmission temperatures?