2002 Tundra Stuck in 4h but not shift into 4wd (1 Viewer)

[UGA LEE 40]

Hey Guys......Long time Land Cruiser Guy (30+Yrs)

However, recently I picked up a 2002 Tundra Sr5.
It has the push button/ actuator 4wd set up.
This week the 4H light started flashing and it seems the t-case is stuck in 4H.
Both drive shafts turn, like the t-case is in 4wd . But the front Diff is not engaging.
Checked power to t-case actuator and both sensors. They have 12.5 v. It wont shift into 4L or 2wd.
Any Ideas- Thoughts- Help Please....
All my other Toyotas have a t case shifter in the floor. I don't know the electronic stuff.
Thanks

 

[J4roe]

Hey Guys......Long time Land Cruiser Guy (30+Yrs)

However, recently I picked up a 2002 Tundra Sr5.
It has the push button/ actuator 4wd set up.
This week the 4H light started flashing and it seems the t-case is stuck in 4H.
Both drive shafts turn, like the t-case is in 4wd . But the front Diff is not engaging.
Checked power to t-case actuator and both sensors. They have 12.5 v. It wont shift into 4L or 2wd.
Any Ideas- Thoughts- Help Please....
All my other Toyotas have a t case shifter in the floor. I don't know the electronic stuff.
Thanks

Sounds like your front ADD is not getting signal or the ADD actuator is stuck. Similar to what happens on the T-Case actuator. I've only had the problem at the T-Case actuator and if you're good at researching and going down rabbit holes you can fix it without having to buy a new actuator or splitting "the case" because of the shift shaft. During my reading for the T-case actuator I also read about how to diagnose the front ADD. I'd search Google and YouTube with those key words but I bet that's what your issue is. You can disconnect the electrical plug at the ADD and use 12v to pin out the ADD itself and see if the motor turns. If it does, problem is wiring or the connector itself. If nothing happens then I bet the motor is stuck in place due to corrosion and water intrusion which is what happens to the T-case actuator through the s***ty breather line that cracks and or falls off.

For the T-Case actuator process is the same. I bought another T-case actuator connector off Ebay and made a 12v harness to run off of a small 12v battery so I could lay under the truck and control the T-case actuator motor by myself without having to press the button in the cab every time for diagnosis. This will move the motor so the shift fork is in the correct orientation when clocking the actuator. Otherwise, if it's not all synced up you'll put it back together and press the button and get the blinking light of death which = the actuator AIN'T ACUATING.

 

[J4roe]

Also, if you're doing this all by yourself put the truck on 4 jacks so you don't have to get in the truck and drive it for a 100 yards every time you think you've made a correction. It's going to be easier in HOVER MODE up on stands than messing with it and having to get in and drive it a few hundred yards to "see" if anything happened vs. making a harness out of another connector and putting her up on jacks and laying there and applying 12v to the ADD motor. That will tell you right away if it's the ADD motor. You don't need the connector but trying to put 12v and ground inside those small connector housings on those small pins you might get a little sparky sparky. Spare connector makes it easy because you plug it in like it's the truck's harness but it's just going to a little small 5ah 12v battery so you can test the motor.

 

[DIRTBIKEUSA]

It’s a common problem where if the 4wd actuators are not used often enough they seize up.

You can try tapping on it (lightly) with a hammer while someone presses the button on and off. If that doesn’t pop it out of 4wd try loosing it (not removing) and jigging it while someone pushes the button.

If that doesn’t work, buy a new actuator.