[Mageeacres]

Rockwell meritor sqhd rearend is made in several configuration from 2.82 to 6 plus. Since the coach was produced when 55 was the norm, changing to today’s faster speeds can be a challenge. First find the recommend sweet spot from the engine Mfg for engine rpm then determine your speed you want to travel at that rpm. Then match the tires and the rearend ratio to make it happen. The engine rpm is the priority due to elevated temperatures are our worst fears. Also install a pyrometer and boost gauge to confirm temperatures. IMHO

https://www.dieselhub.com/tech/ratio-tool.html

Use this handy tool to make comparisons.