04 tacoma 4X4 not engaging

The other day when I went to go to put my truck into 4wd the light on the dash didnt light up. When i got the truck the 4wd light would stick on even though it wasn't engaged (after a few used of moving the 4wd stick the light starting working the way its suppose to). I have done a few troubleshooting steps so far and this what i have.

I have tested to see if its engaging by putting the shifter into 4H then doing a sharp turn to see if the front end jerks, no Jerking. I have put in into 4L and the gear ratio changes but still no jerking with sharp turns. When i shift it in or out of 4wd i hear a click like its trying to do something but nothing happens.

Hopefully someone here that's more knowledgeable than me can assist with identifying the fix. I'm thinking it might be the actuator is not causing the ADD to engage the front axles?

 

Give the actuator on the tcase some love taps with a hammer, could be seized or stuck. had a similar issue on my 02 ranger where the 4wd light would just blink and you could hear clicking like it was trying to engage, anyways turned out to be the actuator.

 

So, when you push the button, the dash light doesn't come on at all?

Assuming the light isn't burned out, that means the truck doesn't even know you're *trying* to put it in 4wd. That could just be a bad switch.

If the light is blinking, that means it knows you are trying to switch to 4wd, but there is a reason (usually mechanical) it can't. Like the ADD isn't aligned properly to engage or the actuator is faulty.

To test it, rather than trying to make sharp turns, put the truck on jack stands. I know my truck doesn't like to shift into 4wd when I'm making sharp turns. That way there is ZERO mechanical force on the wheels/drivetrain.

 

@jbrandt I don't have a button to push for 4wd. my Tacoma is a 3.4L 5MT with a 4wd stick next to the main stick. Yes when i shift into into 4wd (even at a stop) I can hear a single click like its trying to start the process then nothing else happens. No light on the dash lights up, blinks or anything.

all of the jack stands i have are designed for cars not a truck that sits significantly higher of the ground compared to a car lol. But I will look into buying some truck jack stands soon so i can try this.

 

If you're hearing a "click" in the dash, that's your 4x4 relay. If you're hearing the relay, then most likely your transfer case position switches are working. That leaves the wiring to & from your actuator or the actuator.

 

Does it have manual hubs or auto.
If auto I'd make a bet the vacuum lines for the vss are bad.
Look at the top of your front diff there should be a small vacuum line going from the front diff to the driver side inner fender.
Theres is a plastic vss switch there .

 

2004 are all electronic 4x4. No vacuum. No manual hubs.

 

I found this situation was due to lack of use. I got lucky and the actuator loosened up on its own and engages just fine now. Suggest you continue putting it in and out of 4wd and it may loosen. Also same with rear end diff lock. It too freed up with just putting it in and out. This situation can be avoided if you use both of these features on a dirt road on a regular basis. (I use them briefly once a week to avoid this sticking)

 

I'll try putting it in 4wd when I get off work, far as I know my Tacoma doesn't have a rear diff lock. I don't see a toggle on the dash for it but it has a clutch start bypass toggle. Don't really see the use to this toggle tbh lol.

 

How about 2001 - are they electronic or vacuum?

 

Electronic. They stopped doing vacuum actuation in 97 or 98 iirc. I'm sure someone can chime in with the exact year.

 

An update tried putting it in an out of 4wd several times and still nothing. still hear a click when i shift into 4h and the gear ratio is changing when i put it into 4L. while engine was running i engaged 4H and tried to turn the 4wd drivetrain rod and it will not spin, but it will spin if its 2H so my guess is its the actuator? tempted to take a mallet and tap on it to see if i can "unfreeze" it. Friday I may take the piece off and look at the componets inside and maybe take a multimeter and do some tests to see if its receiving a current.

 

If it is the actuator I may need to try and find one from a junk yard, what year range can i look from and would i be able to look at parts from say a 4wd 4runner? Sadly a brand new part is outside of my budget and I would like to have the 4wd fixed before october since I live in Colorado and the roads can be get nasty in the last and first months of the year.

 

I had a similar issue when I purchased my 04 earlier this year. I narrowed my issue down to either a loose plug on the ADD actuator or the actuator loosened up on it's on from use.

Similar to what Actionjackson said, I continued putting it in/out of 4wd for ~2 weeks daily (it would occasionally shift into 4WD, sometimes would get stuck in 4WD). It finally started working full-time after I was going through the troubleshooting from the links below and for some reason (random luck?) was able to get it working again by unplugging the ADD actuator (had a hard time getting it unplugged), then plugging it back in.

Here are some links that may help troubleshoot:
https://www.tacomaworld.com/threads/how-to-trouble-shoot-4x4-actuator.263525/
https://www.tacomaworld.com/threads/2004-trd-manual-trans-cant-shift-into-4h.449373/#post-13172026