I was on the free way and the red trans temp light went on. I also got a code for incorrect 4th gear ratio. I will service trans on Monday. I wonder if the lock up is failing and over heating the trans ?

 

The gear ratio fault code is usually a failing MAF.
The trans temp is usually a bad temp sensor.
Service the trans by changing the fluid and filter and see if the temp light comes back on, if so replace the sensor.
Buy a can of MAF cleaner and clean the MAF following the directions exactly.
If the code comes back after all else then replace the MAF.