Skoolie bus Cummins 5.9 Allison 545 transmission driving up steep hills

Sorry about the bad filming, in this video we are driving our bus over vail pass (10,603ft) just wanted to show how I try to keep my Allison 545 trans cool.
I found what works best is keeping the rpms at 2600 in whatever gear you have to be in
My temp gauge reads 160°, 200°, 320°f
The mark in between 200 and 320 reads 110°c which is 230°f (where I try to keep it below)
Engine temp heats up to 220°f until the fan kicks on and drops it back down to 200°f
Starting the climb in 4th gear until my speed drops to about 45mph and I can down shift into 3rd keeping the rpms around 2600, if the trans starts heating up I’ll let off the throttle until my speed drops to around 25mph and I can downshift to 2nd getting the rpms back up to 2600, once my speed and rpms start dropping after that I let off the throttle until around 15mph drop it to 1st and the rest of the climb I was able to keep it at 2600 rpms with the trans temp around 225