When driving over a lengthy grade there are a few techniques to employ. Going uphill, keep an eye on how the engine is operating. You might want to switch off the air conditioner when climbing a hill to keep the engine cool. Watch the temperature readings and, if you have one, keep an eye on the transmission temperature gauge as well. If you see a rise in temperature release the throttle a bit and downshift. Follow this procedure if the engine seems to drag a bit as well.
Going downhill requires a lot of steady patience to keep the RV under control. Slow and steady wins the race here. Remember this old trucker’s phrase when driving down a sizable grade: “You can come down the hill too slow many times, but you can come down the hill too fast only once.” This also applies to RV drivers. It is always better to start out slower than you feel you should go because downhill momentum is going to begin to build and if you start too fast it is easy too lose control quickly. A good rule of thumb is to remember what gear got you safely up the hill and use that or a gear lower to come back down again. “Diesel engines will have more effective/actual compression braking whereas gas engines only have grade shifting by using the transmission to reduce speed, much less effective than a true compression/exhaust brake that Diesel engines provide.” – David Izbicki
The gear you use for downhill grades should sustain your RV at a comfortable speed and not feel like you are on the edge of rushing down the hill. Some truck drivers use an aggressive braking method that can work for driving an RV as well. It works like this: keep the vehicle with the right gear and find your safe speed. When the RV is at that speed, bear down on the brake until you are five miles an hour below it. Now release the brakes and do not touch them again until the vehicle reaches that safe speed. You should never continuously ride the brakes as this will burn them out.