I keep my Amana with a top freezer in an unheated garage. When the temprature drops to the thirties the refrigertor starts to freeze the contents event though I set the dial to a high temperature. The only way I can keep food and pop from freezing is to turn it off. Is there a way or an accessory that I can insall that will permit the refrigerator to operate in temperatures less than 40 degrees????

Your problem is different than most.
The usual problem when running a fridge at lower temperatures is that the defrost comes on. Heats up the freezer compartment due to the cold ambient temperatures the compressor does not come on after defrost so then the food in the freezer thaws. This may be happening and you have not noticed it.
I would check this as it can put you at risk from food poisoning.

That the food in the fresh food side is freezing sort of indicates that the ambient temperature is much lower than 40 degrees.

Where I am the temperature stays way below freezing all winter so I did a jiggery pokery for the fridge at the cabin. This lets me get some use out of it and I do not have to haul all perishables back home every trip.

I unplug the fridge, remove all the frozen food from the freezer and then put my heater device into the fridge.

Heater device is a standard electrical heater wall thermostat and two light bulb sockets with two 100 watt bulbs mounted on a board. Two in case one of them burns out.
Sometimes I do not get out there for a month or two.
I can set the thermostat around 35 to 40 and do not have to worry about stuff freezing.

I cannot use it as a freezer but then a box on the porch is going to keep everything frozen till spring.