Four wheel drive doesn't engage.

I've got a 2010 Tacoma with the off road package, 100k miles. My Four wheel drive will not always engage; I turn the switch on the dash and the green indicator will flash but not engage
the four wheel drive, I've tried in neutral, drive, reverse, moving and not moving and with a warmed up and cold transmission/engine. Sometime it will engage right away, two seconds say, but other times when I need it, it may take 10 minutes of switching from four to two and back.


Thanks for any advise.

 

Check the vent hoses at the 4wd actuators, if one is cracked, or off that actuator is probably full of dirt and moisture.

Otherwise check your limit switch voltages when it's acting up as outlined in the thread below and post your results.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Thank you very much for the advice: I visually inspected the vacuum hose and electrical connections and all is good. So I took it to the dealer told them it was an intermittent failure problem. They spent an hour diagnosing and told me it works fine. !@#$ Yeah, like I said I knew that. I think it is the actuator sticking from lack of exercise, although I engage it every few weeks. Anyway thanks again for the good information. I am not alone.

 

Intermittent's are pretty much always difficult because the testing needs to be done when the problem is occurring or everything will likely test good.

If you continue to have issues you will need to check the limit switch voltages when the problem is happening to see which one(s) are out of range, dealers typically start shotgunning parts at these unless they have a competent tech that understands the system and how to test it.

 

Mine hasn't worked in 3 years and after taking it to 3 different mechanics they still couldn't figure it out.

 

Take the truck some place where you can drive for miles while in 4x4. Get in 20-30 miles after it engages. It is best to go from 2wd to 4hi while the truck is moving. If it doesn't immediately engage don't stop, just keep driving. Don't try switching off and on. It usually helps ease off the gas and coast for a bit while it is engaging. If the drivetrain is under a load it takes longer. If at a dead stop the gears in the transfer case may not be aligned to let it engage. If you're moving the gears will mesh when everything lines up.

If the truck isn't used in 4X4 regularly the internal parts don't get lubricated and they often don't want to engage. Giving it a good workout to get everything lubed may help. I've seen situations where the grease on the locking hubs has hardened to the point that it won't lock the hubs. All that was needed was to disassemble the hubs, clean the old, dried grease off, relube, and reassemble.

Don't forget to get in a few miles in low range and some time with the rear diff locked. My wife was the primary driver of my Tacoma for several years. We got in some time in 4X4, but not with the diff locked. When we bought her something else to drive and I started driving my Tacoma regularly it took SEVERAL attempts over several weeks to get the diff to lock consistently.

I drive about 5 miles on a dirt road to get into where I turkey hunt. On the way out after hunting every day I'd try to lock the diff. It took several days before it would lock at all. But after multiple attempts it started locking and by the end of turkey season was doing it consistently.

You may have an electrical or mechanical problem. But I've found that most of the time problems like this are because of lack of use. It doesn't cost anything to try. If you do get it working use it on a regular basis in the future.

 

Yours don't work along with thousands of others.
Toyota needs to get with making a better 4x4 switch system.

 

Most of the problems with electronic 4wd systems (not just Toyota's) come from not being used or water getting into the actuators from a disconnected vent hose.

Overall electronic 4wd systems are pretty reliable you just have to engage them once a month or so to keep things from getting sticky and to keep the contacts clean in the actuators.

The 1st and 2nd gen systems can be problematic to diagnose for people not familiar with how they work since they can't talk to a scan tool or set codes, all they can do is flash the lights when something is wrong but we have figured out how to test the 2nd gen system when it doesn't work, you just have to be willing to devote some time with a meter and backprobes to see what's going on.

 

Are all 4 of your tires fairly close in mileage and west?