Musicman,
I have to go along with Ray LeTourneau's thoughts, based on my experience and solution with the same problems you are seeing.
Our 3670 has the fridge installed in the kitchen slide, as does your rig. we're on a long-tern site, in Florida, with the Off Door Side of the rig facing South and were seeing daytime refrigerator temps approaching 60 degrees frequently based on outside temps and sun load.
RV refrigerators are absorption cooling units and are far more "finicky" to temperature differentials than compressor designed equipment, like your home fridge. The flow and pressure changes of the refrigerant happen by the introduction of heat either from an electric heating element or from a small flame. That heat along with the heat that is "pumped" out of the inside of the refrigerator have to be released by the finned coil at the top of the refrigerator chase. As that chase gets hotter from all of these sources, efficiency of the unit goes down proportionally.
In Fridges that are not installed on slides, the upper vent is through the roof which provides much more efficient exhaust of the built up heat than side vented intallations. There are documents available on the web, which Dometic describes the considerations for installing their products in slide out rooms. Their fridges are not designed any differently, and these criteria for side vented installations are left to the RV manufacturer to follow.
First, I added about 2" of fiberglass insulation between the top of the slide and top of the refrigerator. Access to this area is through the upper vent on the outside of the slide. This served to keep heat from being trapped in this area as it is above the upper vent, and it may also keep that heat from warming the freezer.
Second, I installed the resistor kit Ray LeTourneau referenced.
Third, I added another 12VDC muffin fan in the chase to improve cooling airflow. This was difficult as the fan is in the chase midway between the upper and lower vents. I also replaced the fan temperature switch located on the cooling fins in the top of the chase to bring the fans on at a lower temperature. These fans run much more than previously, which might be a concern if you camp on battery power only for long periods.
Fourth, I added a 12VDC muffin fan inside the refrigerator on the cooling fins add some efficiency and to keep the temperature inside the fridge more even.
Our fridge maintains 37 degrees on the highest setting now regardless of the outside temperature and sun loads. The only trade off is that with the humidity here in Florida, I defrost nearly every week as I enjoy an ice-cold beverage.
I can't say that my mods are are fully "factory approved" and may have warranty implications as well, but they have worked for us.