Ford F150: How to Change M5OD Manual Transmission Fluid

Replacing the transmission fluid can ensure your Ford F150's transmission lives for a long time, with slick shifts and less grinding. Read on to learn how to do it yourself.

By Bassem Girgis - May 23, 2016

This article applies to the Ford F-150 (1988-2008).

Although the factory doesn't require the transmission fluid to be replaced except for at every 60k miles, when your Ford F-150 starts racking up the miles, replacing the fluid more often is a great way to protect the transmission. The process of replacing the transmission fluid is rather simple and can be done by anyone with some mechanical experience. If you haven't replaced your transmission fluid in a long time, then read on to learn how to do it.

Ford F150: How to Change M50D Manual Transmission Fluid

Materials Needed

  • Drain pan
  • Fluid pump
  • 15/16 socket
  • 3 quarts ATF transmission fluid

If you've got a 4 x 4, chances are you don't need to jack the truck up to get under it. But for most people, start by getting the truck up on jack stands, and as level as possible. Even though the M5OD is a manual transmission, like many modern manuals, it gets filled with common automatic transmission fluid. You will probably need about three quarts of fluid to fill it, but you will know when it is full because fluid will drip out of the fill hole.

Step 1 – Remove fill plug

Before draining the transmission, it's a good rule of thumb to remove the fill plug first. The last thing you want is to drain the transmission, then get stuck not able to fill it back up. The fill plug is the one towards the passenger side. Use your socket to remove the fill plug.

Remove fill plug
Figure 1. Remove fill plug.

Step 2 – Drain transmission

Place the drain pan under the drain plug, then use the same socket to remove it. Let the transmission drain completely.

Let transmission drain completely
Figure 2. Let transmission drain completely.

Step 3 – Fill transmission with fresh fluid

Make sure you close the drain plug, then using your fluid pump, pump fresh fluid into your fill hole until it overflows. It should take about three quarts of automatic transmission fluid (ATF). Once the fluid overflows, tighten the fill plug and clean the area.

Pump fresh fluid until overflows
Figure 3. Pump fresh fluid until overflows.

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