2005 XL2 Engine Running Temp, RPM and Gear Selection

[PrevostNewbie]

New to the forum, apologies if this has been covered in length, I've been unable to find anyone with this specific issue.

2005 XL2 with a Series 60 Detroit and Allison Transmission is running regularly just shy of 210 for the engine temp.
I've been told the fan kicks into high at 210, this seems to be happening.
I've had both my high and low relay's checked and the fan is running both low and high.

While pulling hills, I'm forced to downshift manually to get the RPMS up to 18/19K, this could be as low as 3rd gear at times.
Today while running in very hot temps 109 from Barstow to Kingman, I was stuck mostly in 3rd gear running around 50 mph on a minor grade just to keep the RPMs up to cool the engine enough to not hit the 230 mark and red warning lamp.

This became a major issue when I would hit the big climbs and at one point was as low as 1st get barely making the grade.

What's going on here? The fan clutch is new, the belts feel tight, the relay's work, the fan works. Why am I doing wrong or what I am not doing?

Any and help is greatly appreciated.

Jordan, you might already know this but take it slow and keep the RPM's up. The way I drive my bus is I run about 1/2 throttle, and keep downshifting if the RPM's drop below 1700. I think i had to drop to first gear maybe once in my last trip thru the Utah Mountains where we had 12 and 14% grades, Usually i am climbing in second gear and the engine is about 210 degrees. I have like 5K miles on my bus and I am still learning how to drive it, i think we all can learn from the experience of how these machines move down the road, there is no bus that will allow you to keep the pedal mashed to the floor without downshifting and being cautious in 100 degrees plus temps climbing grades. If they say they can they are 1) lying or 2) showing off.