How to Check the Transmission Fluid on a 2003 Oldsmobile Alero. It took manufacturers like GM a while to get into the import-fighter game. From the 1970s through the 1990s, domestic manufacturers didn't fight import manufacturers so much as they did sign on. Back then, most "domestic" compacts were really just "captive imports," rebadged to appeal to American consumers. The N-platform though, despite the fact that it was never much beloved by enthusiasts, was at least a truly American attempt at capturing compact ground instead of remaining captive to import manufacturers. Checking and changing the transmission fluid on a 2003 Alero isn't as simple as most would prefer, but neither is it particularly difficult.
Lift the front of the car with your floor jack and secure it with jack stands. Lift the rear of the car to the same height, and secure it with jack stands. It's important that the car's level, or you won't get a proper read on the fluid level in the transmission. Crawl under the car and look at the engine-side of the transaxle, just below and to the right of the place where the axle-shaft plugs into the case. You'll see a 7/16-inch bolt in the side of the transmission case. This is the transmission's drain/fill plug.
Position a drain pan under the transmission to catch spills. Remove the plug with a socket and ratchet, and dip your pinky finger into the hole. When filled properly, the fluid will come up right to the bottom edge of the hole. If it's overfilled, the excess fluid will simply spill out of the hole and into your drain pan.
Drop your hand pump's inlet tube into a quart of Dextron-III transmission fluid, and stick the outlet tube into the drain/fill plug hole. Start pumping transmission fluid into the hole until it starts to overflow. It should take about 7 quarts. Install the plug, and tighten it to 12 inch-pounds with the torque wrench. Lower the car, start the engine and run the shifter through all of the gears with your foot on the brake.