We currently have a 25' Class C with the MB V-6 diesel engine. The unit tracks down the road very solidly. The only issue we have is lack of interior space. We started looking for an entry level Ford ...
I can easily drive with one hand in my 33 foot Ford chassis MH. I'm actually quite surprised how stable it is even with a trailer in tow. To me it sounds like something is amiss but since other owners of your rig are reporting the same problem, not sure what's going on there.