Anytime you get a MIL on the cluster you need to find out what code you have in CM.
From the CM code we can help you find the problem.

 

Actually it can lock in first too according to Mark K. See here: https://www.ford-trucks.com/forums/1...l#post14667332

So you had a bad PSOM.

 

I think I left out the word "Manual First".
It does not lock in "Manual First" under any conditions.
This is stated in the "E4OD Automatic Transmission Reference Manual" in chapter "Theory/Operation" page 8.
I think we are talking about the E4OD transmission in this thread.



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sooo not to sound dumb but how dose this differ from the o/d on-off on the end of the shifter?

 

Without reading this whole thread all over again.
How does what differ from the O/D button on the end of the stalk?

If this is what you are asking:
O/D has nothing to do with the TCC lock up as the transmission will do a TC lock up in O/D and out of O/D.

 

OD (overdrive) is fourth gear in the transmission. When you press the button on the end of the shifter and the OD OFF light is on the transmission won't shift to fourth gear. Torque converter lockup can happen in third gear and fourth gear, and in some limited amounts in first and second gears, too.

 

 

The first thing to do is to check codes. Here's How

Then decide if you want a work around, or want to fix it. Fixing it may be easier than adding a switch.

 

Is there a switch on the 89 c6?
@55mph The rpm is 2600....should b 1800 or so, also no power on a 10 degree grade...terrible gas mileage!!!!

 

No, the C6 doesn't have a lockup converter. Never did.