AXOD Highway RPM

[joesho_gb]

I've looked, searched, and all I can do now is ask.
When I bought the car in October last year, prior to making a lot of major repairs such as the trans fluid / filter, valve cover gaskets, having the secondaries stuck open because a broken vacuum canister, and that kind of stuff; going at 55mph the tach was at about 2k, 65-70mph was about 2,300 - 2,400.

Since probably mid January, 65-70mph is almost 2,800rpm. 55 is about 2,300 or so. CEL does come on, pulling codes is the rear O2, but that's the only code now.
The torque converter is locked on OD, so it's not slipping.

What would cause this to run so high? What can I check or replace to get it back down?

About 75% of my driving is interstate, and I'd like to get it back down so I stop sucking gas.

Thanks

 

[projectSHO89]

The SHO uses the AX4S transmission, not an AXOD....regardless of what is stamped on the pan.

Count your shifts and make sure you can identify the 1-2, 2-3, 3-4 shifts and the TC lockup.

The TC will not lock until the transmission fluid reaches a specified temperature as detected by the TFT sensor. Hard to do in cold weather until you've drive a fair distance.

 

[joesho_gb]

Project
My trans pan says "AXOD SHO", so that's why I thought I had the AXOD.

As for the shifts, I can identify all shift points at TC lockup.
Is there a sensor on the trans that monitors the TC speed that would make my tach go so high?
Maybe it was a fluke when I bought it, and this is it's normal operating speed at highway, but like I said, it seems really high.

 

[joesho_gb]

I just pulled codes, and I'm getting a 636 code, which per this site
http://www.troublecodes.net/Ford/eec-iv.shtml is a transmission fluid temp higher/lower than normal.

Where is the trans temp sensor located?

 

[rubydist]

I'm speculating that the tft sensor thinks the trans is cold and is preventing the torque converter from locking up, resulting in the higher rpm.

 

[projectSHO89]

Unless the transmission is at operating temp, the 636 will occur.

The TFT is internal to the transmission.

Make certain you have fulfilled all prerequisites before pulling codes.

 

[joesho_gb]

Well, I was correct in saying that my Transmission pan says "AXOD SHO". I had to climb under there today to get access to the rear o2 sensor. But, if it's not an AXOD, then I can live with that too.

One thing that I forgot until I got under there, I bypassed the radiator and ran straight into the trans cooler.
I didn't think of this before due to the fact that the engine was already revving high prior to making that change.

Maybe I'm not thinking right, but if the TC is locked in place, when you press the gas the tach doesn't jump a lot, like when the TC is cold, correct?

Or is there another way to tell if the TC is locking or not?

 

[whiteguy3]

I've had that code a number of times. It's just as rubydist said. We had this same issue in another post not too long ago. Fairly normal in the winter months. I bet you will not have that issue again when it gets warmer..

 

[FOMOCOTOSHO]

Check out my thread listed here. Hope this helps..

http://www.shoforum.com/showthread.php?t=106200