Thought I'd give an update to my original findings. I'll once again preface by saying that these are my findings only. I'm all ears if someone is able to provide additional information on how this system operates. I'd also be grateful if anyone is able to provide the section describing Rear Air Suspension from the RAM Shop Manual.
I'm very satisfied with how my truck (see sig) rides both empty and loaded. Loaded in my case is a Grand design 2930RL S-Class Solitude with approx 2500 lbs pin weight. While some may say 'its a 3500 and is supposed to ride stiff - get over it' my reply is that its also my daily driver and I know that with some work these trucks can be made to ride better.
My definition of a smooth unloaded ride? Prior to any of the things I did, I noticed that the rear was much stiffer than the front. When going over a bump the front would be fairly smooth while the rear would jolt my behind. After the adjustments etc, my rear suspension now feels just like the front. While it will never ride like a half ton, the sharpness of the ride is much more reduced.
Since I last wrote in this thread, we've towed the 5th wheel approx 500 miles which has allowed the rear suspension to settle. While my drivers side bag was still soft, it was not as supple as the passenger bag was. My assumption all along has been to have the bags empty when the truck is empty with full fuel. In my case the drivers bag has always been more firm than the passenger bag. To get the drivers side height sensor to let more air out of the bag, I needed to elongate one of the mounting holes. I used a dremel to remove a small amount of material as shown in the photo. After doing this, the drivers bag is now as supple as the passenger bag. Note that I've never anything to the passenger side of the suspension - my goal all along has been to get the drivers side the same as passenger via adjustment of the height sensor.
In summary, my combination for a very acceptable ride empty is the following:
1. Height sensors adjusted so that both bags are supple when truck is empty and fuel full.
2. Rear tire pressure is 42 lbs or less - note that I have the 20 inch wheels on mine. Either way, take advantage of the load range charts. There is no reason to keep the rears at 80 lbs! Front air pressure is 60 lbs.
3. Keep a full fuel tank - this seems to give the best ride.
So in order to achieve the softer ride the idea was to make sure the bags are both soft at empty? So essentially you are on the springs only?
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