4x4 not engaging?

First time poster.

Picked up a 2004 double cab SR5 4x4 in June of 2020 (now is December). 4.7 V8 running great with 165k on the odometer.

Just got hit with a snowstorm, and wasn't able to engage the 4wd. When I push the 4HI button, I can hear a clunk sound coming from the front end, but the light just flashes, and the 4x4 does not engage.

I've done some reading on this, seems like the most common culprits are a bad position sensor or a bad actuator motor on the transfer case.

Anybody else had this problem, and if so, what did you do to fix it?

 

Bump, so you get another pass on the main page. Good luck!

 

Were you moving while you tried it? My truck shifts into 4HI a lot smoother when I'm already moving. There is a chance the previous owner never engaged 4WD and the actuator is frozen like you mentioned. The owners manual states we're supposed to driver a certain amount of miles each month in 4WD.

@empty_lord might have some advice for you.

 

+1 on moving when engaging 4HI.

 

I've tried engaging 4HI while moving too. Pushed the button and drove around under 20 for 5-10 minutes, same result- can hear something trying to engage from the front end after pushing the button, but the light just flashes and no 4wd.

 

If you hear a clicking from the front noise that “should” be the front diff actuator, you need to pinpoint what your hearing. Technically the front diff shouldn’t engage till the transfer case is in gear, so you might actually be hearing the transferscase shift into 4hi but the front diff is stuck open

 

Yes, my bad. I believe it is the transfer case actuator I'm hearing. I'm assuming the actuator itself is good since I can hear it trying to engage, so the problem is possibly somewhere else. Maybe the 4HI position sensor?

 

Is this the first time you've tried using the 4wd? Did it work when you originally purchased the truck?

 

I didn't think to try it out before purchasing, so just realizing the problem now

 

Try going in reverse for a 30 yards or so with it engaged? Then go forward and maybe reverse again if it doesn’t work the first time.

 

The actuator on the front diff can partially 'sieze' in place if not used every so often. The grease will 'set' or 'harden' enough to bind the actuator.

Sometimes you can turn 4x4 on/off to free it up, sometimes you can bang on the actuator with a deadblow or rubber mallet to free it up too while trying to engage it.

 

You can try the dead blow approach, but more than likely a new front actuator is in your future. I replaced both of mine back during the summer.
If you do end up replacing the front ADD actuator, drain the gear oil first, because it will run out the actuator mount area when you remove the actuator. Refill with fresh gear lube after the actuator is replaced.

 

this

 

On my Tundra 4wd will only engage after I press the button and turn the vehicle off then back on.

 

There are some YouTube videos on ADD repair. The contacts inside the ADD usually need cleaning.