Our Greyhawk came equipped with the J-Ride package which included Hellwig overload helper springs, Hellwig anti-sway bar, MorRyde body isolation mounts, and Bilstein shocks. This is the best equipped F-450 motorhome chassis I have ever seen from any manufacturer. Unfortunately, we had a similar problems with out 2014 Greyhawk 31FS. I have a commercial driver's license and it was scary to drive the Greyhawk and I have driven large commercial trucks. It constantly bottomed out on the rear on even very slight driveway or roadway slopes. The Bigfoot landing jacks would hit even slightly sloped driveways. The steering would not stay centered when driving. The ride was also extremely harsh when hitting road seams.
I changed the following things to resolve the issues:
The alignment was way off (camber and toe) - Jayco Paid for this
The Bigfoot landing jacks were installed incorrectly with too low of clearance to the ground (5" vs. 7" - 8" clearance) (The dealer moved the jacks up one or two adjustment holes) which gave approximately 6 7/8 clearance. I had Hellwig airbags added which brought the clearance up to 7 3/4" at full inflation (100 PSI)
I had a Roadmaster steering stabilizer added to replace the Ford steering stabilizer
I plan on adding a Hellwig front heavy duty front anti-sway bar to replace the Ford version
The changes Jayco and I have made have had a tremendous difference in the drivability of the Greyhawk. It is much more predictable and stable. I drove home I a very strong wind (and rain) storm from the dealer yesterday and even with 65 MPH gusting side winds I was able to control the Greyhawk. The airbags really helped to soften the ride substantially when going over bumps and seams at highway speeds. I was surprised at how much a difference the airbags made to eliminate the "bang" noise when both rear wheels go over a road seam. As soon as I get the front sway bar installed it will help with the front leaning at a different rate from the back when being passed by trucks. If anyone on the forum wants information including part numbers etc. please let me know I am happy to help.
2004 Chevrolet Silverado 3500 LT with a 2004 Jayco JayFlight 29BHS
2014 Greyhawk 31FS with a 2007 Tahoe toad
2014 Thor Palazzo 33.3 with a 2007 Tahoe toad