How To Replace A Modulator Valve In A Toyota Highlander

The thought of replacing a transmission component can be pretty intimidating. But, if you’re a Highlander owner with a bad modulator valve, you actually can replace it with just a few wrenches. We’ll show you how.

Preparing For the Project

Highlander 06

To do this project safely and efficiently, you’ll need a car lift. You can use floor jacks, jack stands, a hydraulic lift, or a Kwik-Lift. Whatever you use, you just have to make sure that your lifting method is safe and secure. You’ll be spending some time underneath your Highlander.

As for tools, the only thing you’ll need is a set of wrenches.

Last, but not least, you need to have a replacement OEM modulator valve ready before starting the project. You can either buy one at your nearest Toyota dealer or order a genuine OEM modulator valve from an authorized online seller like us. To find the right part number, simply do a search on your Highlander in our catalog. Our best selling modulator valve is part number 44050-48191, which is for 2006 and 2007 Highlanders.

Steps to Take

Old mod valve

To replace the modulator valve on your Highlander, take the following steps:

  1. Lift your Highlander. Be sure to do it safely.
  2. Remove the vacuum hose, which runs between the intake manifold and the transmission modulator valve. If you find fluid inside the vacuum hose, it’s OK. It only means that the diaphragm inside the modulator valve has broken and you’re fixing the problem by replacing the valve. Drain the fluid out of the vacuum hose if necessary. (Your engine has probably burned some transmission fluid that was sucked through the vacuum line. This won't hurt the engine.)
  3. Unfasten the bolts holding the modulator valve onto the transmission.
  4. Remove the modulator valve by twisting it counterclockwise. Pay attention to the actuating rod, which might fall out in the process.
  5. Place the actuating rod inside the new modulator valve and then insert the new valve into the receptacle hole. Push until you hear a slight snapping sound, which indicates that the o-ring has been seated.
  6. Fasten the bolts holding the modulator valve in place.
  7. Reconnect the vacuum hose to the intake manifold and the new modulator valve.
  8. Check your transmission fluid level, and add fluid if needed. (If the modulator valve has been bad for a while, you will probably need to add fluid.)
  9. Lower your vehicle safely and then take it out on a test ride to see if the new modulator valve is working properly.
Written by Jason Lancaster