The icemaker requires a temp below 13 - 17 degrees to cycle by it's internal T-stat. Set any thoughts of the icemaker aside and sick to the thought the new refrigeration unit isn't working properly. That is if you have eliminated door seals. When a freezer has frost built up on one side over the entire freezer compartment it is generally a refrigerant sealed system problem. Listen for any gurgling sounds. If present then you are losing cooling liquid (ammonia)from the cooling coil unit.
There is also the chance the cooling unit was miss installed and the insulation wasn't replaced properly or the coil wasn't sealed to the box properly. But I will bet you are losing ammonia from the coil assembly. These can be damaged easily while installing.