I moved to the top of a mountain in California to work at a boarding school three years ago. Since then, I have gone up and down the mountain’s winding and steep road at least 3 times/month. I thought I was smart to downshift my automatic Subaru Forester as I go down the mountain - I can do the 1/2 hour trip from 5000 feet without touching the brakes. Now I am getting a new car - an Infiniti G35x and I really want to treat it right. Should I be braking instead?
You are doing it right. Use the same technique for your Infiniti.
good advice, stevef. The transmission is working whether the brakes are applied or not. Use the brakes too often and you’re in a “run away”. Been there, done that, didn’t want the tee shirt!
You are doing it right. It is not only better for the car, it is far safer.
You’re doing exactly the right thing. I once drove through the interior of British Columbia in a Hyundai Accent, and going through mountain roads, I discovered the Accent was unable to provide enough engine braking when going downhill, so I had to use the brakes on every hill. Which overheated them and caused the to be useless. Which meant I was going towards 180 degree hairpin turns at 60-80 km/h. With no shoulder. Or guardrail. And a 1000 foot cliff beyond. So yeah, it wasn’t fun.
Keep doing what you’re doing.
It’s unanimous. You’re doing it right. Keep up the good work.
I think you should use your brakes instead.
Ha ha ha just kidding!
We do a lot of mountain driving, and going down steep slopes we gear down with the automatic to the gear that will significantly slow the car, but might still need a little use of the brakes.
Like others, I learned the hard way with a camper behind, and having the brakes fade on me; a scary occurrence.
As long as it’s still in gear and not neutral, you should be fine. I do this with my Civic when going up railroad overpasses. It keeps my revs up(it’s a 4cyl, what do you expect? 
) so I’m not lugging my engine when someone in front of me wants to do 25~30 up the hill instead of the posted 35~40mph(depends on which overpass it is)