I have a 2003 GMC Envoy 2WD. What are the 3, 2, and 1 gears for? And when do I use

[SoDone]

them? Which one would I use for mountain driving?

 

[Ba12348]

3,2,1 are lower gears, for hauling a trailer or driving hills, they force the transmission to stick with one gear instead of letting it switch for best speed with the load it has

 

[Santa]

They are used if you have a heavy load, heavier load, or rocky surface...use number 1 for rocky surface

 

[Molson02536]

them? Which one would I use for mountain driving?

It's used to give you more throttle response in relative to your speed, in Simple terms. 1-2-3-(4 OD) are progressive gears that work there way from low to high gears, as the RPM's on engine rises. The speed of the Envy is limited to the gear ratio from 1st to 4th, so as your engine's RPM is around 3,000 in first gear. Your Envoy is limited to a max speed of around 20 MPH and at 4th gear with your engine at 3,000 RPM, your max speed would be around 80 MPH. The 2nd and 3rd gear will also have a max speed in relative with the engine's RPMs.

With that said, when you place the gear shifter in 1st, your transmission will not shift in to the next gear limiting your speed to what the engine's RPMs are which is controlled by your right foot. If you place it in 2nd, 3rd, or 4th, the transmission will not shift past what ever gear your have placed the gears shifter in.

With driving your Envoy in a set gear say like 3rd will limit the Envoy's speed and will give you more throttle response to your Envoy's speed as you can control the engine's RPM with the gas pedal.

Take note that your transmission will run hotter in the lower gears and your Torque Converter clutch will not lock up, causing the transmission fluid to heat up.

Hope this helps, kinda hard to explain in simple terms on what the great selections are for.