How to Change the Transmission Oil in a 2004 Yukon

When it comes to doing a transmission service on a 2004 GMC Yukon, there are two lines of thought. If the transmission fluid is tainted with a brownish color, it has considerable worn clutch material suspended in the fluid. These fine particles of clutch material will converge around the small ports in the valve body and cause operating problems in the long run. A standard fluid and filter change will eliminate the clutch material attracted to the magnet in the pan. If the color of the transmission fluid is still cherry red, this is good preventative maintenance. If the color shows far-reaching contamination, a regular service will leave the torque converter, cooler lines and radiator full of the contaminated fluid, which will quickly contaminate the new fluid. It needs to be flushed at a service facility. This involves disconnecting the cooling lines and with the engine running, replacing all the fluid.

Instructions

1

Block the rear wheels so the truck doesnt roll. Raise the truck with the floor jack and place jack stands under the frame just behind the front tires. Place the drain pan under the transmission pan.

2

Remove the transmission pan bolts, starting with the rear bolts at the crossmember. Remove all the bolts except the bolts at the front of the pan. This is so you can remove them last, and slowly, to allow the pan to drop and drain the fluid into the drain pan gradually.

3

Remove the front transmission pan bolts, slowly stopping every so often to allow the transmission fluid to drain more. Remove the pan. Pour the remainder of the fluid into the drain pan. Hold the transmission pan over the drain pan and clean all the residue out of the tranny pan using the brake cleaner. Remove the magnet and wipe it off with the clean cloth and put it back in the pan. Make the pan perfectly clean.

4

Inspect the pan gasket. If it is rubber, you can reuse it. If it is cork, replace it. Pull the filter out of the valve body with a little twist. Look to see if the rubber O-ring came off with it. If it did it will be on the neck of the filter pipe. If not, leave it in the valve body and remove the one on the filter neck. Just use one O-ring either in the valve body or on the filler neck.

5

Install a new O-ring on the new filter. Push the new filter into the valve body. Install the pan and snug down all the bolts in a crisscross pattern. Do not over-tighten. Lower the truck to the ground.

6

Open the hood and pull the transmission dipstick out. It has a red cap and is located on the passenger side near the firewall. Fill the transmission with 5 quarts of transmission fluid, using the funnel.

7

Start the engine and while applying the brakes, shift the transmission through all the gears, hesitating in each gear for a couple of seconds. Place the transmission in Park and leave the engine running. Insert the dipstick all the way and pull it back out to check the level. Fill the transmission as needed, in small increments, to bring it up to the full mark. Do not overfill.