Engine/Transmission (1994 - 1998) Random kickdowns and temp light

[JRitz]

My trans started randomly downshifting from overdrive and the trans temp light comes on. It will stay on for about 2 or 3 seconds and then go out. Then the trans will kick back into overdrive. This is all at part throttle, freeway speed with no load or Trailer. Could my trans temp sender be going bad? Perhaps a PCM Problem? Please help, I don't want to smoke the poor thing!

 

[Joe G.]

One way to test it is to remove the connector from the temp sensor and put a 1K ohm resister in the connector. This tricks the PCM so that it will respond as if the trans was at operating temperature. I have mine that way and am using the fitting where the temp sensor was for a transmission temp gauge sensor.

 

[GHansen]

What Joe G. said about the resistor is right on. I did mine permanently and sealed it with heat shrink tubing and dielectric silicone then zip tied it up out of the way. As it turned out, I havent had shifting problems of any kind at all since.

 

[LDPetersen]

I just replaced my TSS last week. Was intermittant for months. Same problems you are having. Works great. Could not find one at the local parts places, but you might find one. I went to the dealer and paid $40. oo. Larry.

 

[JRitz]

TSS being the transmission shift solenoid? I tried replacing the temp sensor and it still does the same thing.

 

[biggy238]

NAPA has the TSS... It's the same one used on the 727's up until the new models...

I think mine was $25-$30





I think his is the temp sensor though...

 

[Joe G.]

JRitz,



You have a '95 which has a 47RH. Kyle has a '96 which has a 47RE. I don't think your trans has a TSS.

 

[JRitz]

I didn't think it did. That's why I asked.

 

[Jschafer]

Joe G what is the normal range of the trans temp on your gauge what do you think is max temp. I agree it sound like the temp sensor to me.

Joe

 

[Joe G.]

I really don't know since I run John Deere hydraulic oil instead of ATF. Mine runs pretty cool. I had to fake it with a resistor because I drove all the way from here to Roseburn, OR without it getting warm enough to satisfy my PCM to let it shift to OD. I very seldom see 200° on mine. 150° or less is what I see most of the time.

 

[Howard Durand]

Joe,

Why John Deere hydraulic oil?

 

[Joe G.]

Howard,



I will e-mail you some info.

 

[biggy238]

Transmission Speed Sensor=TSS... I was just stating that NAPA had them... I didn't realize it was indicating something else. . sorry.



Hydrualic fluid from John Deere... .

 

[LDPetersen]

My fault I should have said TTS not TSS. Mine was a trans. temp. sensor. Larry.

 

[Hummin Cummins]

I'm interested in this JD Hydraulic Fluid concept also I run Lubrication Engineers 7500 in mine, which is a synthetic Allison Hydraulic oil. (says hydraulic oil on the container, not transmission)

 

[Joe G.]

John Deere Hy-Gard®

 

[JRitz]

So I tried the 1K ohm resistor in the trans temp sensor connector and the thing still exhibits the same problem. Does anyone know which to wires in the PCM connecter the temp sensor is (and maybe where the PCM is too so I don't have to go digging)? I Think I'm just going to solder the resistor into the wires right at the PCM to eliminate the wires as the problem.

 

[Joe G.]

If the resistor didn't fix it then you have something else wrong. I think I would look for a ground problem at this point.



You can do a continuity check between pin 42 and the connector without the resistor. Pin 4 on the PCM is ground. The wire on the temp sensor connector that connects pin 42 to the temp sensor connector is violet. The other one connects to pin 4 (ground) on the PCM. It is black with a light blue tracer.

 

[JRitz]

Great. I'll try that next. If I can find an obvious problem there, can I just solder the resistor between the wire coming from pin 42 to the wire coming from pin 4, right at the PCM? Plus is the PCM under the hood or under the dash? Thanks again!

 

[Joe G.]

There is only one PCM. It is on the firewall behind the air box. I don't think the resistor is the problem. I don't thing soldering on the PCM is a good idea either. If the continuity is ok, then soldering on the PCM is not going to help the problem. If it is not ok, then you have some sort of ground or connector problem. Might even be corrosion in the connector on the PCM. If you don't have a service manual then you really need one to trouble shoot this much more than you have.