How do you change the transmission fluid on a 2001 Oldsmobile Alero? How necessary is it? I don't think I have done it and the car is over 150,000 miles

Remove the transmission oil pan replace the filter bolt the pan back on put 4 liters of DEXTRON V1 start vehicle run to operating temp. under the vehicle on the right side were the drive axle is there is a 10mm bolt remove it keep adding transmission fluid till it comes out that hole then reinstall the bolt DO NOT SHUT THE EHGINE OFF TILL THAT BOLT IS BACK IN

I would say its an absolute must that you do this because the car is 8 years old. Similar to changing oil, there should be a drain plug and a filler cap, although I have never actually worked on an alero. Also a good idea would be to pull the transmission fluid pan and clean out the metal shavings off of the magnet inside. This will give the new metal shavings inside the transmission something to cling to so they donot travel and wear out your transmission. Be sure to replace the gasket if you do this.