Engine/Transmission (1994 - 1998) AutoTrans Erratically Downshifts, Cold Weather

[Turbo_Bob]

1996 Dodge truck, Cummins, with a 47RE trans, recent O/H but now experenced (erratically downshifting out of overdrive due to cold weather, cold radiator temps, cold trans temps).



The radiator temps were as cold as 140F and the trans temps were 95F.



The trans was droping out of OD, going into 3rd gear and cycle back into OD at 5 second intervals, then erratically drop into second gear at times.

Will stay in OD for 10 to 30 minutes then start over again.



While on the long trip pulling a trailer with the cold air it was in the 30's F.



What was done as a roadside temporary fix, draped a towel in front of the trans cooler. That brought up the the temp to 150F. That got the trans to operate as normal.



What needs to be looked at or brought up to my trans guy for better diagnosis info for him ?



Is there something in the trans like a temp sensor?



Radiator therostat replacement, have the orginial in there, what is the new "slow cycling therostat part number" ?

 

[robbiesworld]

The following items affected my transmission, lockup/overdrive.



Trans temp sensor (in trans hardline near trans. ) Bipassed with resistor. Under 5 bucks @ Radio Shack

Brake pedal bumping into my brake light switch. Adjusted switch. FREE

TPS Throtle position sensor. Replaced. Under $120. 00 Dealer

ESS Engine speed sensor. Replaced $78. 00 Dealer (this also causes other problems with tach,charging,overdrive,cruise control.

 

[Turbo_Bob]

The following items affected my transmission, lockup/overdrive.



Trans temp sensor (in trans hardline near trans. ) Bipassed with resistor. Under 5 bucks @ Radio Shack

When the trans guy O/H the trans they replaced the sensor, it may be a different value from stock ?



What is the rating of that resistor ?



Trans works perfict when the trans fluid and radiator fluid is warmed uped.

 

[robbiesworld]

When the trans guy O/H the trans they replaced the sensor, it may be a different value from stock ?



What is the rating of that resistor ?



Trans works perfict when the trans fluid and radiator fluid is warmed uped.

I couldn't remember so I searched around and found some threads. it looks like a 1K resistor is what I used.



https://www.turbodieselregister.com...1994-1998/180568-transmission-temp-gauge.html

 

[RAmy]

good info, could have used something like this a few years ago myself. My old s10 with a 4. 3L and auto used to do this when it was really cold too (as in negative temps). wouldnt do it right off the bat tho. I would let it warm up for 10-15 minutes and drive easy for a while, then all of a sudden 15-20 minutes later it would backshift for a few seconds then back to OD, sometimes wouldnt go back into OD the rest of the way home from work (about 25 miles at the time). I sold the truck in the spring when it was warm out. Never did it when temps were warmer.

 

[Turbo_Bob]

I couldn't remember so I searched around and found some threads. it looks like a 1K resistor is what I used.



https://www.turbodieselregister.com...1994-1998/180568-transmission-temp-gauge.html

Thank You.

 

[robbiesworld]

Thank You.

Hey get back to us so we know if this solves your problem?

 

[Turbo_Bob]

Hey get back to us so we know if this solves your problem?

Problem solved, replaced the stock thermostat which allways had very wide temp swings, 140F to 185F. Put in the new improved slow cycling thermostat and the truck warms up quicker, runs 180F to 190F.



The culpret turned out to be the connection at the temp sensor on the auto trans, pulled it off and cleaned it, pluged it back in and the trans performed great.

 

[edgeman]

I was wondering what that part number for the slow Cycleing Thermostat is if you can please tell me that would be awsome!

 

[BSMcCauley]

I was wondering what that part number for the slow Cycleing Thermostat is if you can please tell me that would be awsome!

Don't remember the # right off, but I got mine from Geno's Garage.