under fan b calibration you should have 3 scalars labeled "Engine or Transmission Temperature" 1 through 3. set them all to "AE" as per the scalar descriptions:

Engine or Transmission Temperature 1
Location: 70CD


Set to A2 (00A2 coolant temperature) to use Fan B for cooling engine.
Set to AE (00AE transmission temperature) to use Fan B for cooling transmission.


Engine or Transmission Temperature 2
Location: 70E5


Set to A2 (00A2 coolant temperature) to use Fan B for cooling engine.
Set to AE (00AE transmission temperature) to use Fan B for cooling transmission.


Location: 710A


Set to A2 (00A2 coolant temperature) to use Fan B for cooling engine.
Set to AE (00AE transmission temperature) to use Fan B for cooling transmission.