Nissan Repair: 1997 Nissan Altima - Max miles, valve cover gasket, worry free travel

Question
1)I am having a 97 nissan altima with 77K miles on Board, What is the maximum miles we can use this model cars without any major problems starting to occur (engine or transmission).

2)Whats that over drive option available in my car? Is it ok to drive the car with OD set to ON in roads where max speed limit is 35.

Thanks

Answer
1. with proper maintenance, forever.   twin cam 2.4 liter motors are VERY reliable.   things you must keep an eye on are the oil seals, front and rear main, the valve cover gasket, and timing chain and tensioners/guides.   they are well built and only fail without oil.  


2. Think of overdrive as 5th gear.  it will only engage at a certain speed+rpm anyway.  My OD is always engaged on my 95.  You have nothing to worry about with this car, just keep an eye on the above things and enjoy years of worry free travel.