I got a question I just wanted to know if it normal for a front and rear diff to get hot will the car is idling? I am doing my brake in on my Rc engine, I stopped the engine after running a tank at idle and picked it up from the back of the car with my hand under the rear diff to realise that is it extremely hot, under the front diff was not as hot as the rear one. Is this normal?

Thanks
Pyro