4L60E Transmission Flush Guide

Does your truck’s transmission need new fluid, but you’re not too thrilled about having to pay so much for a dealer to do it? Well, there’s an easy, cheap way to go about doing it yourself that is completely safe for your truck and its transmission. Follow these easy steps to have your transmission fluid flushed and filled within an hour.

Required Tools

  • 3/8-inch brass transmission cooler line fitting
  • 3/8-inch clear tubing
  • 5/8-inch crescent wrench
  • Hose clamps
  • Adjustable wrench
  • 15 quarts ATF
  • Catch pan or bucket

4L60E Transmission Flush

Removal Procedure

1. Locate the upper transmission line on the passenger side and remove the line from your vehicle’s radiator. Pull the black plastic bracket back to prevent damage; it is protecting an e-clip that should not be removed. Use a wrench to loosen the fitting.

2. Once the line is removed, connect your brass trans cooler line fitting. Then connect the clear tubing, securing it with a hose clamp so no leaks take place.

3. Route the tubing to your catch pan or bucket. If needed, use tape to secure the tubing to the bucket.

Important: you will want to place the catch pan or bucket by the driver’s side so you can see the fluid flushing as you go.

4. Now you will begin to flush the fluid. Start the engine, and fluid will begin to pump into the bucket via the clear tubing. Pay careful attention to the tube until you either see or hear bubbling, and then shut the truck off immediately. It will take roughly 30 seconds to pump out 3 to 4 quarts of fluid. Add 3 to 4 quarts of new fluid to the transmission dipstick tube until it reaches the “full” line on the dipstick, and repeat.

Important: you will repeat this process 3 times, and you should notice the change in color—it will go from a dark magenta color (especially if dirty) to a red color. Once this color change happens you will know you’ve flushed all of the fluid.

Installation Procedure

1. Once the fluid is completely flushed, remove the brass line fitting and the clear tubing, and reconnect the transmission line.

2. Fill the transmission with liquid to the “full cold” line on the dipstick.

3. Start your vehicle and allow the transmission to warm up.

4. Once it has reached operating temperatures, check the dipstick and fill to the appropriate line if needed.

You’re all done! Easy enough, right? Be sure to save the materials used for this procedure for future uses.