Changing the transmission fluid in your Chevy S-10 truck depends on whether the truck has a manual or automatic transmission. You need to change the fluid for both types every 30,000 miles. If you drive an S-10 with automatic transmission in extreme conditions, however, you need to change the fluid every 15,000 miles. Check with your mechanic for details specific to the year, especially with the type and amount of fluid needed for your truck.
Raise the truck and support it on jack stands. Place a drain pan underneath the transmission at the drain plug; rags and newspapers also help.
Remove the drain plug on the transmission, which is the lower of the two plugs and will likely require a hex wrench to remove. Allow the fluid to drain into the pan then reconnect the plug.
Disconnect the fill plug, located above the drain plug.
Fill the transmission case with fresh transmission fluid using a syringe bottle or hand pump--make sure this tool has never been used for any other task. Add fluid until it starts leaking out the fill hole then replace the plug.
Lower the car.
Raise the truck, support it on jack stands and place the drain pan under the transmission pan.
Unscrew and remove the mounting bolts on the side and the rear of the transmission pan. Loosen the bolts on the rear by about four turns without removing them. Pry the pan loose with a screwdriver and pour the fluid into the drain pan.
Remove the pan by removing the remaining bolts and pour any remaining fluid into the drain pan.
Clean the entire transmission pan with solvent and dry it with compressed air.
Remove and replace the filter on the transmission by rotating it out of its retaining clip. Remove the filter's seal from the transmission with a screwdriver if it didn't come off with the pan. Install a new seal with a socket and install the new filter.
Connect a new gasket to the transmission pan--make sure the pan's surface is clean--then install the pan back onto the transmission, tightening each bolt a quarter turn at a time.
Lower the truck off the jack stands using the floor jack.
Add 3-1/2 to four quarts of automatic transmission fluid through the filler tube in the engine compartment.
