How to Change Transmission Fuild

Transmissions are hydraulically controlled units which utilize fluid to change gears. The fluid also operates to cool the transmission by directing heat away from the transmission as it flows through the cooler lines. Unfortunately, the fluid's ability to lubricate and cool the transmission diminishes over time. Given enough time, the transmission will fail as a result of ineffective fluid. Therefore, the transmission's fluid should periodically be replaced with fresh fluid at the interval specified by the vehicle's owner's manual.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Wrench
• Container
• Rubber mallet
• Transmission pan gasket
• Gasket sealer
• Funnel

1. Drain the fluid from the transmission by either removing the transmission's drain plug or by removing the pan. Many transmissions have a drain plug on the transmission's pan, which is located on the bottom of the transmission. Use a wrench to remove the drain plug, then allow the fluid to exit the transmission into a container. Reinstall the plug once the fluid has finished draining. If the transmission does not have a drain plug, its pan must be removed. To remove the pan, remove the bolts which surround the lip of the pan with a wrench, then tap on the side of the pan with a rubber mallet to dislodge it.

2. Install a new pan gasket and install the pan to the transmission if the pan had to be removed. Ensure that the inner lip of the pan, as well as the surface on the transmission where the pan attaches to, is free of old gasket material. Coat both sides of a new pan gasket with gasket sealer, then place the gasket against the pan. Press the pan onto the bottom of the transmission, then install and tighten the pan's retaining bolts with a wrench. Allow at least 1 hour to pass for the gasket sealer to dry.

3. Open the vehicle's hood and withdraw the transmission's dipstick tube. Insert a funnel into the dipstick tube, then pour new transmission fluid into the funnel in small intervals. Periodically insert the dipstick into the dipstick tube to determine the fluid level within the transmission. Fluid should be added to the transmission until the fluid rests just below the "Full" mark located on the tip of the dipstick.

4. Start the engine and allow it to reach normal operating temperature.

5. Shift through the transmission's gears several times to allow the fluid to circulate throughout the transmission.

6. Check the fluid level, while allowing the engine to run, by withdrawing the transmission's dipstick and reading the marks on the tip of the dipstick. The fluid should be just below the "Full" mark on the dipstick.

7. Add fluid, if necessary, by pouring fluid into a funnel which has been placed into the dipstick tube.

References

• Motor's Auto Repair Manual, Ralph Ritchen, 1968

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