What is the proper way of using overdrive,how and

HI. The OD option is mainly used for extending your MPG(Miles Per Gallon), during long distance travel. It is not recommended for city driving. When in overdrive, the transmission will tend to shift to the highest range possible, during travel. This is only an asset during long distance travel(Highway). If used during city driving, you will notice erratic shift patterns, and lots of down shifting as well, during acceleration. This is common when using OD in city driving.

The recommended usage is regular D in city, and OD during highway travel. Using the regular D during city travel, will decrease the unnecessary downshifting that is needed when using the OD option during city driving.

If you are not climbing steep hills or towing, leave it on all the time. Turn it off for low speed/high strain driving like towing, climbing and off-roading.

i hope this helps
-matthew