Overdrive?

Is car with automatic transmission not suitable for hilly areas ? I heard that it gets defective soon in hilly areas . Is it true ?

Not true. Except that the life of the transmission depends upon how rashly the car is driven or how badly it is maintained. Other than that, the AT box just does its job as it is supposed to do, whether in hilly areas or in normal conditions. Preferably, the transmission must be kept in lower gears as far as possible, by using the appropriate option such as O/D off switch, etc.

This will aid better pick up when needed and will avoid gear hunting and abrupt shifts. IMO, frequent and abrupt shifting MAY shorten the life of the transmission. 

Where there is a wheel, there is a way!

What is OD switch ?

OD switch in automatic transmission is an option where the transmission avoids higher gears, ie 4th or 5th etc to give better power delivery in lower gears in situations such as hill climbs etc where the usage of higher gears wont be fruitful for driving. The engine shifts at higher RPMS and in some cars, it may shift at the redline too. 

Where there is a wheel, there is a way!