How to Change Transmission Fluid in a Chevy Truckby Gregory CrewsUpdated November 07, 2017
Items you will need
Ten ounces of transmission fluid
Transmission pan gasket
Changing the transmission fluid in a Chevrolet truck is essential to the truck's ability to shift accurately. The transmission is a hydraulic machine that is run by bands that shift the vehicle when the engine speed is too great for the gear in use. The system works off pressure created by the hydraulic fluid. Years of use can cause the fluid to break down and become contaminated. Changing the fluid and filter is a must to maintaining the life of the transmission.
Removing the Pan
Locate the transmission underneath the truck. The transmission is located just behind the motor. The transmission pan is the bottom portion of the transmission.
Check the pan to see if there is a drain plug. If there is, you can drain the transmission pan before unbolting it. Have a pan to catch the fluid. Loosen the plug with a crescent wrench. Allow all of the fluid to drain and then tighten the plug. If the pan does not have a plug, proceed to unbolting the pan, in Step 3.
Locate and unscrew all of the bolts positioned around the drain pan. Hold the pan up with one hand once the bolts are loose. This is especially important if there is no plug on the transmission pan. Lower the pan once it is loose.
Empty the transmission fluid into a drain pan. The transmission pan needs to be emptied and cleaned before re-installing it.
Scrape the old gasket material from around the pan and the bottom of the transmission. This will ensure the pan does not leak when the pan is re-installed.
Unscrew the filter with a socket wrench. The filter is located in the transmission housing.
Installing the Pan
Clean out the pan with brake cleaner, which will help clean the old fluid out of the pan. If there are any metal shavings in the pan, you'll have to clean those out, too.
Tighten the new filter to the transmission with the socket wrench. The new filter needs to be changed with the fluid. Place the O-ring on the filter suction side and be sure it is sitting firmly before attaching the filter.
Place the gasket on the transmission pan. Be sure the bolt holes in the pan match up to the holes in the transmission pan.
Raise the pan to the bottom of the transmission and start the bolts. Do not tighten the bolts until they are all started.
Tighten all the bolts snug with the socket wrench. The pan is ready for the fluid.
Filling the Fluid
Open the hood to access the engine compartment. Locate the transmission oil dipstick toward the back of the engine. The transmission dipstick is designated by a red cap.
Insert a funnel into the fill tube where the dispstick was inserted. This will be where you pour the transmission fluid.
Pour in five quarts of fluid. Check the transmission oil level after the fifth quart to ensure you do not overfill.
Pour fluid in as needed by the half quart. Check the level after you fill. This method will take longer but it will help you avoid overfilling.
Start the vehicle and let it run for at least a minute. Place your foot on the brake and shift through all the gears. Start at reverse and shift down to Low 1. Place the vehicle back in park.
Check the level. Fill if the level is low.
Place the dipstick back in to the tube. Push it down firmly to lock it to the tube. Close the hood to complete the task.
Consult your owner's manual to find the correct type of transmission fluid for your truck. There are two possible types, depending on the transmission and age of the truck.
Do not use anything but brake cleaner to clean out the transmission pan.
Use extreme caution when working underneath the truck. Be certain the parking brake is set and the wheel is chocked. Park the truck on level ground.
Contact your local parts store or recycling center for disposal of the old transmission fluid.
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