My 2007 Allure (400ISL, CM850) air compressor is a Cummins part # 5301096. The recon number is 5301096RX. Replaced mine last year - part was about $1,800US for a recon.
They are a b***h to replace. Starter removed - coolant and oil lines are tough to get a wrench on - frame rail adds a few swear words to the repair.
Towr: 2007 Country Coach Allure 470 - 37 Sunset Bay Cummins 400 ISL, Coach #31563
Toad: 2016 F150 King Ranch - 3.5L EcoBoost 4x4 Supercrew (curb weight 4,775 lbs)
Toad: SOLD 2007 Jeep Grand Cherokee (yes, it has a Hemi) (curb weight 4,720 lbs)