QuestionHello Sherry I have a 1996 Toyota Corolla 98K miles (automatic transmission) and I was wondering if using the Low Gear when going up any type of hill will hurt my engine at all? Will shifting to Low Gear use more gas mileage? Is it better than 2nd gear? I have started to use the Low Gear a couple days ago. Thanks.
AnswerHello Hayato,
Your automatic will shift down by itself if necessary to climb a hill. That's the beauty of an automatic, it knows by internal fluid pressure how many rpms are efficient in each gear.
The only way you can harm your engine is by reving the rpms too high. If you have a tachometer, never rev it into the yellow or red zones. A lot of automatics don't have tachs. If you don't have a tach, just try to avoid going more than 10-15 mph in low. Shifting into low while going faster than 15-20 might also damage your transmission. Old valves are more delicate and can't withstand the pressure that high.
Shifting an automatic into 2nd is really just limiting it to 1st or 2nd gear and avoiding the highest gears. This is used mostly in towing where you hear your transmission shifting constantly from higher gears down to 2nd, then up again. It can also be used for engine braking when travelling at highway speeds down a steep hill.
Low gear in an automatic is mostly designed to control your speed going slowly down a very very steep hill. For example, I use it on my Jeep to keep from making the brakes too hot, and maintaining a steady crawl speed down a steep rocky hill. Mine goes less than 5mph in low, so that I can control it on rocks.
You should never need to shift into 1st or 2nd going up a hill, the transmission will not shift up farther until its up the hill anyway.
Using low gear a lot will definitely hurt your fuel economy. Any time your rpms are high, you are burning more fuel than is necessary to move the vehicle.
Hope this helps,
SherryB
