trans temp problem

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Feb 21, 2009 | 08:09 AM

#16

1975StroppeBaja

Cargo Master

Joined: Apr 2006

Posts: 3,215

Likes: 7

From: WV

Sounds to me like your gauge is working fine. Last night I drove home (about an hour drive, across one mountain) and my gauge was basically dead on 120 deg. It was about 15 deg outside.

Feb 21, 2009 | 07:30 PM

#17

Mark Kovalsky

Frmr Ford Trans Engr

Joined: Aug 1999

Posts: 24,704

Likes: 2,625

From: SE Florida

Quote:

Originally Posted by JockD

Mark, Is there a way to modify the stock gauge system to make the temperature gauge jump up to "hot" at say, 200 degrees? Adding a resistor or something? That would give a savvy owner better warning of pending overheat.

The PCm sends trans temp data to the instrument panel. The instrument panel has a microprocessor that decides what to do with that info. You need to reprogram the instrument panel micro to change how the gauge operates. A resistor isn't going to do it.

Feb 21, 2009 | 08:27 PM

#18

tex25025

Post Fiend

Joined: Oct 2005

Posts: 10,626

Likes: 7

From: Plano TX and Brentwood TN

Quote:

Originally Posted by Mark Kovalsky

Could you do that thru PTDIAG?

Feb 22, 2009 | 01:55 AM

#19

soutthpaw

Laughing Gas

Joined: Jun 2005

Posts: 1,009

Likes: 1

From: Colorado

My OTC Genisys scan tool actually gives me 2 readings for trans temp the before and after trans cooler temps... I was running it on the truck today and the before cooler temp was around 150 and the after cooler temp was around 115 120 seems the stock cooler does about 30F reduction in temp. ambient temps were in the 50's today... Really making me consider an external trans cooler... as the stock cooler in the radiator is only at the temp of the coolant that has just flowed thru the radiator...

Feb 22, 2009 | 08:11 AM

#20

Mark Kovalsky

Frmr Ford Trans Engr

Joined: Aug 1999

Posts: 24,704

Likes: 2,625

From: SE Florida

Quote:

Originally Posted by tex25025

Could you do that thru PTDIAG?

I don't know what PTDIAG is, so I can't answer this. It would need to let you access the micro in the instrument cluster, download the software from it, modify the code, and reload the modified code back into the micro.

Quote:

Originally Posted by soutthpaw

My OTC Genisys scan tool actually gives me 2 readings for trans temp the before and after trans cooler temps...

How does it do that? Did you add another sensor? The stock trans only has one sensor.

Quote:

Originally Posted by soutthpaw

as the stock cooler in the radiator is only at the temp of the coolant that has just flowed thru the radiator...

...which is quite a bit cooler than the temperature when it entered the radiator, or the radiator isn't working.

Feb 22, 2009 | 01:04 PM

#21

krewat

FTE Leadership Emeritus

Joined: Jul 2002

Posts: 42,561

Likes: 421

From: Long Island USA

My 4R100 sits at around 150F on the hottest day of the summer, unless I am really REALLY working it.

During the winter, the gauge never moves.

Aftermarket Autotemp gauge.