Re: Transmission Shifting in Sub Zero Temps

From: Ethan Schwartz (ethan@ethanschwartz.com)
Date: Fri Jan 16 2004 - 08:41:47 EST


To quote the bible (1997 Service Manual):

"The PCM prevents engagement of the convertor clutch and overdrive
clutch, when the fluid temperature is below approximately 10*C (50*F)"

I'm positive that I read in another section that OD will not engage if
the "ambient temp" is below -10*F... which I guess must mean ambient
engine bay temp? Because if they were reading the outside temp it seems
like there would be no OD ever in super-cold places. The reasoning was
because "the transmission fluid could be frozen"... I wish I could find
the section that said it....

I think the lock out might be reset by an on-off-on key cycle... I drove
to work at 4am the other day (-3* I think?) and had no OD at first... I
started out and went about 10mi (a couple of miles @ 70 w/ engine ~3k),
stopped to get the coffee order, and came back out for the other 10mi
and OD was working. It set no MIL so I assume that it was working as
intended.

-Ethan

david.clement@verizon.net wrote:
> We had the coldest morning (-7 F) in my recollection in the Boston area today.
> I know the tranny does not shift into 4th until it is up to temperature. In my
> 14 years of owning Dakotas that has never been more than a mile or two of
> driving, but it's never been this cold either. Today I drove my entire 14 mile
> commute to work without it shifting to 4th, shifting between 1-3 was normal.
>
> My question for those that regularly see sub zero temps is it common/normal for
> it to not shift into 4th on a drive of that length? My engine temp was up to
> the normal point on the gauge within 3 miles of the house.
>
> Dave Clement
> 89 SLT+ CC 4x4



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