Replaced various parts and still overheating on inclines

2016 wrangler with a 3" lift running 35. Around town all is good. Start to climb medium inclines it start to get hot. Gauge goes to about 3/4. Took it to the dealership. They replace the radiator and cap. Flushed the engine. They have replace both heads and gaskets. It is now back at the dealership with the same issue. Anybody have the same issue or give some advice.

Thanks in advance.

 

Sounds like an air flow issue...got a big obstruction or winch up front? Thermostat working properly and correct replacement? Correct type of coolant used during ownership? Check the relays to the electric fans and make sure they work at high temps or with a/c on.