how to change settings from 2 wheel to 4 wheel

Their should be a knob on the dashboard that says "2H, 4H, N, 4L". Stop the vehicle and move the knob from "2H" to "4H" and now you should be in 4H which will allow you to do highway speeds in "4x4" mode and when you go to "dry pavement" switch back to "2H" so you don't ruin the transmission. Does this vehicle have AWD ? If there is an emblem that says "AWD" on the back tailgate or on the dashboard somewhere, then you can not shift into any "4x4" modes. The transmission and center electronic coupling will tell itself when it "does" or "does not" need AWD with out your input at all.

"AWD" - All Wheel Drive, good for speeds from 0 - 80+, "2H" - good for speeds from 0-80+, "N" - Neutral, "4L" - good only for speeds up to 30 mph but will go thru almost anything.

I have a GMC Envoy, with a knob that says the following, "2w, auto, 4↑, 4↓, & when you put it on Auto it feels like something is hitting, but drives good in 2w

Why does the 4x4switch liight blinkwhen I turn it into 4L or 4H?

If your Envoy is in need of a major tune up I highly recommend driving in 4-wheel drive 2 wheel drive will only make it burn gas. It will pull harder on the transmission after your qnap be sure and put it back on two-wheel drive.

2h is better round town

Can you drive in auto? My knob it's broken and I have it on suto, not sure if that's were it should be

Do u leave the auto on or put in 2H