towing 5th wheeler

We have purchased a 27ft Ultima 5th wheeler and have set up our Landcruiser 2008 V8 tray top with a Reece 5th Wheel hitch. The vehicle has good power on the tow but we experience quite a lot of 'jerking' on the road. Has anyone had experience with this and may have some answers to how to iliminate this problem. Only genuine comments please.