[Richard]

Some Newells had adjustable tag pressures, many do not, the tag air bag pressure is the same is the drive bag pressure. You can easily tell. If you have one six pack in the rear passenger engine compartment, the tag pressure is not adjustable. If you have two six packs, one will have regulated air going into it. That is the adjustment for tag pressure.

You have stated the ride height appears correct, meaning somewhere between 11 and 12 inches measured at the square tubing just inside the fender flares. If the front were higher, it would kick the rear down.

I just measured and I have 11.5 inches clearance at the hitch receiver with a standard hitch, not a 20K hitch. However I only have about 8 inches between the ground and two skid bars welded to the frame.

Can you post a pic of your hitch the wheels you reference? A previous owner may have added a heavier hitch, and or those skid wheels you reference.

In general, Newell hitches are far closer to the ground than other Class A motorhomes. The 20k hitch hangs even closer than a standard hitch.