Oh okay, and what brand spring mounts did you use?
During your research, you'll get a sense that most spring mount designs are home spun.
Spring mounts or torsion free mounts as they are often referred too, allow the vehicle frame to twist and flex as the vehicle rolls over uneven terrain. With their use, the vehicle frame isn't restricted in movement by an attached rigid body. These mounts also prevent torsional forces from being transferred to the camper body. Over time, torsional forces will cause cabinets to come apart, plumbing fittings to fail and window and door seals will start to leak water and dust.
Keep in mind that a torsion free mount design has to allow the camper body to separate or lift off the frame rails, but also has to guide the body as it settles back down. They also have to prevent the body from crashing into the back of the cab during a sudden stop and yet prevent the body from sliding off the vehicle frame rails to the rear and/or roll off the side.
The only commercial torsion free mounts I've come across were from
United Truck & Equipment, designed to mount a water tank to a truck. I can't recommend these as there isn't any data on bolt size and grade, nor is there any data on the springs. Having the four rear mounts being rigid, will certainly restrict the attached body from shifting forward, backward and side-to-side movement.
If you haven't noticed yet, the frame on the FG is different from that of the two wheel drive. There's a step-up in the frame rails that has to be taken into account. The body builders guide in a link, in a prior post, shows how to deal with this.
On the flip side
Don & Kim Greene traveled the world with their Unicell body rigidly mounted to their truck. Here's a link to their build;
QuestConnect.
Hope this all made sense!
