I have had the truck in my sig about 4 months...never had o/d. The o/d on off button will turn on/off but the only thing it affects is how soon the TQ will lock up in 3rd. If I turn o/d off it will lock up almost immediatly after it shifts, otherwise it waits till I wind out a little more.

I just replaced the solenoid in the tranny and still the same thing. The funny part was I ordered the solenoid thru advance auto. The first one I got only had 1 solenoid, where the factory one had 2 on the same bracket. I took it back and had advance order the one they showed as dual but for a 47re, which didn't exist in '94. The other funny thing is my haynes repair manual says the '94 trucks only had a 3 speed auto called the 37rh. I know that's BS since I it had a dual solenoid and an o/d on/off button. I can't seem to find any fuses which would be used for this. So what can I try next?

 

Your trans temp sender could be bad/unplugged or bad connection.
Sensor won't allow OD until it thinks the fluid is 70F.
Check it out, driver's side a little ahead of the tranny on the cooling line.
To check the sensor unplug it and jump across the two wires going away from it with a 1000 ohm resistor (Radio Shack, 25¢)

 

If you replaced the 2 pack solenoid i think that was the tcc (lock up) controll and the overdrive. the other one that fits straight up in the valve body is the electronic governor. if that goes bad it wont shift either. you can plug a gauge or use a scan tool to verify if the psi is going up and down with engine speed. another one is the output shaft speed sensor on the driver side tailshaft. also the spedometer has to be working correctly.
This one could be a little tricky to work out since the 94 didnt come with a 47re but somehow you got one.
if you need i can copy some pages from the manual when i get back to the shop.

(edit) the other single solenoid that goes into the valve body sideways is the trans temp sender and ?? (i forget) on the 47RE

 

The parts store didn't show his 94 to have the 2 solenoid harness, I think he did get the right one though. Its as infidel said, it could be the trans temp sensor. I've also seen them with play in the connector, and it not go in, or go back and forth. If your speedo is working, and your getting lockup, there's not much else to check. Because your getting lockup, then the TPS is working.

 

Well I still didn't get this fixed. Unplugged the wires to the temp sensor and started the truck and a "trans temp" light comes on. I jumped the wires with a 1k resistor and the light went out but still no o/d. **** transmission anyhow!

 

My 97 did this exact same thing. Ended up tranny needed to be overhauled. We tested every thing on that trany and every thing checked out.

 

Ok, some I'm still at the same place. The TQ locks up fine, just never any shift into O/D. If I continue to let the PCM handle TQ lock up and wire the O/D solenoid to a switch, will I run into problems with TQ lockup going berzerk when I manually engage O/d with the switch?

 

You can reduce trans life by shifting with the t/c locked. Let me suggest you go to the trouble of wiring up a switch to "force" OD to work on level ground. Get up to 50 MPH on level ground with only enough throttle to maintain speed. If you switch o/d on and it does not work, you need a trans shop to further diagnose. If o/d engages, could be PCM output or something else like wiring. Add the wire to manually engage o/d and then let us know.

Ronnie

 

So is the resistor trick just a temporary thing just to prove if the sensor works or can you leave it the for good?

Wayne

 

Best not to make it permanent unless you have a tranny temp gauge.
The resistor trick is the common way to trick the tranny into thinking it's running at normal temps when the stock sensor is replaced with the sensor for an aftermarket gauge. This can only be done on '94-'95 because the sensor on the RH tranny is in the output line to the coolers. On the later RE tranny the sensor is internal, there is no port on the output line for an aftermarket sensor.

 

I just had a thought....with the OD switch off (normal driving) the TQ should not even try to lock up. Might just be a problem with the PCM but i would try checking the switch and wires to the PCM and also the ouput shaft speed sensor.

 

tripler, I disagree. With OD off, the PCM will lock the t/c on level ground in third gear around 30 MPH in my truck. With an aftermarket valve body, you can lock the t/c in second gear at 30 MPH or at any speed in second gear with a manual switch.

This is how it works in my "95. It may be year specific or RH specific.

Ronnie

 

So I found the wire that comes out of the tranny for O/D. I just have to run it to a switch and then a ground right?

 

Follow the instructions here http://www.tstproducts.com/Torque%20...p%20Switch.pdf

 

Well I still can't get it to go into O/D even with a switch, so I am going to the next best thing...getting some 37's. I figure 55 is about the most I can get to on the speedo without a lot of throttle...that'll be about 68 with 37's. Guess that'll be good enough for interstate driving when needed. The lockup switch makes for a good smoke switch though.