Re: [A/S] Transmission fluid - Heat Death Spiral

["Oliver Filippi" <ofilippi@xxxxxxxxxxxx>]

Hunter,

The reason for the sudden failure of your transmission fluid is the sequence
of events which compound the problem.

Automatic transmission fluid is both a hydraulic fluid to actuate the
transmission and a lubricant, and a coolant fluid.

When excess heat is generated in the transmission, it goes to the fluid and
then to the transmission cooler.  If the heat is not dissipated fast enough,
the fluid gets still hotter.

This heat causes the transmission fluid to break down, which reduces its
lubricating qualities which causes additional internal friction which in
turn generates even more heat, thereby accelerating the breakdown of the
fluid.  And the death spiral continues!

I think a transmission temperature gauge should be included on any vehicle
with an automatic and a heavy duty towing package.

I think you are going to see more attention on the part of automakers toward
towing features on their vehicles in the future.

For example, my 2002 3/4 ton Chevy Silverado pickup came with a transmission
temperature gauge, as well as a "Tow/Haul" control on the shift lever to
allow the driver to change the shift points to reduce heat buildup under
heavy towing loads. (Hill climbing, for example.)

In addition, the computer controlled transmission will automatically change
the shift points if it detects the transmission overheating.  It also
displays a message to that effect on the instrument panel "message screen".
At least this way you know you are running in dangerous territory and can
stop to let the transmission cool off.

Another thing to look into (on which I have not done much research) is the
use of a synthetic automatic transmission fluid.  The synthetic fluid should
be able to take higher temperatures without breaking down.  But the higher
temperature could fry some of the other components in the transmission.  But
at least you wouldn't get the accelerated "death spiral" transmission fluid
breakdown sequence as with the conventional fluid.

Oliver Filippi