You have a lot of miles on your transmission, or perhaps it'* not shifting right. It'* time to remove that old fluid and filter. You can take it in and pay over $100 to have it done, or do it yourself for half that price. You will need the correct transmission fluid. Please look at the label closely to ensure you have the correct fluid. There are differences in make, and year. You will also need a filter and gasket for your car. These generally come together in a kit. You will need ramps or a good jack with jack stands. And finally a large pan to catch the fluid. A oil change pan will work, but you will fill it nearly to the top. 7 quarts of transmission fluid is what tends to come out. The only special tool that will be needed is a inch pound torque wrench, not a foot pound, a inch pound wrench. It is very important that everything be very clean. You do not want any dirt getting in to your transmission.
Jack up the front of your car and use jack stands.
Or put it up on ramps.
Get everything laid out, fluid, a extra gasket. Mine had a reusable gasket so I didn't need one.
Locate your tranny pan.
It'* going to be a big mess. Get a large pan to catch the fluid, a few extras are a good idea. Crack the bolts on the pan loose. Loosen the back bolts a bit more so it will drain from that area. When the fluid stops you can start to remove all the bolts.
Remove the pan and set it aside
Wipe it down good. Check the magnet for any metal shavings. If you see a lot of shavings you may need to consider getting the transmission serviced.
You will then remove the filter. There are no bolts or clamps holding it in place, but you may need to do a lot of wiggling to get it to come out, they can be a bit stubborn at times. After removed it should look a bit like this.
Install your new filter.
Make sure the gasket surface is clean, remove any left over gasket or dirt. Whip it down real good. Now put your pan in place and get a few bolts started. then snug up each bolt
Now with a clicker type inch pound torque wrench torque each bolt to 120 inch pounds. That'* inch pounds, NOT foot pounds
Once the pan is torqued you will need to fill the tranny with the correct fluid. You will do this threw the dip stick tube. You will need a funnel. Make sure you get GM fluid. You will need to add fluid, then start the engine and go threw the gears, then add more fluid and go threw the gears again. It will take some time to fill the tranny back up.
Congratulations, you just saved yourself a lot of money and only spent about a hour and a half to do it. Feels good to do your own work don't it?