4wd won't engage, troubleshooting

I have a 03 Tacoma V6 AT, push button 4WD. The 4wd is not engaging, and the light is not going on. Could you help me troubleshoot this problem? I’ve got the truck on jack stands now, I’m ready to get this project going so that I can get up to the mountains over the winter break.

What I have done so far… when I push the 4wd button, I can hear the actuator on the differential clicking. When the front wheels are off the ground, and the truck in 2wd, I can spin the front drive shaft by hand. When in 4wd, I can not spin the font drive shaft by hand. But in 4wd, when I spin the front tires, the front drive shaft does not spin.

So, is there an actuator located on the front axle, passenger side? I see something that looks like that. Any suggestions how to trouble shoot that, or what to do next?

Thank you!

 

I am not a mechanic, so I can't help... but you may find something if you search under ADD (Automatic Disconnecting Differential) which is how we have 'auto locking hubs' on Tacomas for shift on the fly ability, but don't need to drive backwards to unlock them.

The ADD uses a fork on one of the front axles next to the differential. I have heard of that fork not working electrically... but until it is repaired you can manually engage it... you can go in and out of 4WD, but your front drive will not be free wheeling... no biggie, locking hubs weren't on WWII Jeeps afterall.

Good luck!

 

Make sure your vacuum lines are hooked up and/or don't have any vacuum leaks.

 

Not the same thing completely but here is my thread from this time last year. Mine wouldn't come out of 4WD. I ended up needing an new acutator. Good luck!

http://www.tacomaworld.com/forum/technical-chat/64055-wont-come-out-4-wheel-drive-help.html

 

Thanks, I'll check that now...

 

No, the 4wd is absolutely not working. Power is not delivered to the front wheels.

 

When I spin one wheel, the other wheel is not affected.

 

PERFECT. Thanks for the help. I'll report back.

 

I used the links to confirm that the ADD disconnect is bad. The resistance measured at the plug was out of spec. Great link - thanks. I've ordered a new part from trdparts4u.

Final report to come when it's installed.

 

Well crap, I just installed a new actuator and the 4WD is not working still. Too bad. I did the trouble shooting according to the manual, and the resistance measured indicated that it was shot. Now I guess I'll do the same for the new actuator, and check the relays. After it stops pouring rain. Which should be in four days.

 

Same thing has happened to me, except I have an 05 Tacoma TRD TRD, V6, 6 Speed. When I turn the switch, the light does not come on. I use 4WD quite often, and it's been working up until today, although the last couple times I used it it it didn't go out or come in to 4wd as easily as it should. It could be the actuator has gone bad, and it seems they are known to go bad, but before I change it out I wanted to ask if there's often easier solutions, like is this truck known to get leaks in the vacuum lines or something?

I don't want the same thing to happen to me, order a new actuator and replace it only to find it doesn't work. What's my best course of action?

Thanks