Toyota Tacoma: 4WD Diagnostic Guide

Nothing is sadder than having the capability to go off-roading but having an issue that's stopping you. Read on to learn how to diagnose your 4WD system.

By Bassem Girgis - February 18, 2016

This article applies to the Toyota Tacoma (1996-2015).

The 4WD system on your Toyota Tacoma allows you to take your truck off the road. Having the ability to go off-roading is like having more freedom than 90% of the people on the road. Having an issue with your 4WD system takes you from being absolutely free to being absolutely stuck. Owning a Tacoma with 4WD requires some more maintenance than those without 4WD, so the more you stay consistent with your maintenance, the less chances of something going wrong. This guide will shine some light on the things that can go wrong with your Toyota Tacoma's 4WD system, and what you can do to diagnose it.

Toyota Tacoma 4WD Diagnostic Guide

Material Needed

  • Flashlight

Step 1 – Check differential

It could be leaking.

Checking the front and rear differential is a piece of maintenance that should be done often. Often time, the differential could start leaking without giving you any signs. To avoid any damage to the gears, always use your flashlight to check for leaks on the ground and around the front as well as rear differentials. If you hear loud grinding with your 4WD lever, louder than usual, you could be low on differential fluid. Check the drain bolt, as it could leak, then check around the differential because the leak could be the main seal.

Toyota Tacoma 4runner 4wd issue problem diagnostic troubleshooting
Figure 1. Check differential for leaks.

If the differential isn't leaking, proceed to Step 2.

Step 2 – Grinding noise

You could be using your 4WD system wrong.

The most common reason for grinding noise, even more common than low differential fluid, is using the 4WD lever wrong. The first thing you need to know is that you should never activate the 4WD system on dry pavement. The second thing you need to understand is switching between 4WD gears. It's not like your average automatic transmission, as the 4WD lever needs to be pulled hard and fast; also, you should expect grinding noise, just not too loud. When switching gears, be sure you're at a slow, coasting speed, and make sure you're on flat ground. Finally, when shifting back, put your transmission in neutral, or if you have a manual transmission, just step in the clutch. Properly knowing how to operate your 4WD lever can be the difference between a damaged system, and a safe off-road trip.

Toyota Tacoma 4runner 4wd issue problem diagnostic troubleshooting
Figure 2. Make sure you're operating your 4WD system properly.

If you're using the 4WD system properly, proceed to Step 3.

Step 3 – Check lever's cable

It could be broken.

If you're switching between gears with your 4WD lever and nothing is happening, your 4WD lever's cable may be broken. It is a cable connected to your lever from one side, and to your gears from the other. When you shift the lever, the gears get pushed in place. To inspect it, remove the center console, then follow the cable going from your lever to your transfer case. It is, however, a difficult job, letting a professional do it may be a good investment.

Toyota Tacoma 4runner 4wd issue problem diagnostic troubleshooting
Figure 3. 4WD cable.

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