1st Gen Tacoma wont go into 4WD

Hello, my 2001 Tacoma 3.4L V6 5spd manual will not engage in 4WD. When you push the button to engage in 4Hi you can hear the actuator moving but the green light on the dash does not come on and 4WD is not activated. I checked the driveshaft that goes to the front diff from the transfer case and after 4wd button is pressed the driveshaft to front diff spins but the power isn't going to the front wheels. Depressing the 4wd button allows front shaft to be spun by hand (as it should) but I cant figure out why power isn't going to the front wheels. Don't think its a blown front diff. Is there an actuator at the front diff that allows it to receive the power and send it to the front wheels?

 

This part of your comment is confusing to me.

When the 4WD button on the shifter lever is not depressed, the front driveshaft out of the t-case should be able to be rotated by hand. When that same button is depressed (what would normally be "activating 4hi) you should not be able to rotate the front driveshaft by hand.

It is the opposite of what you are stating.

 

Does the little green 4WD dash light turn on if you move your t-case shift lever to the 4lo position?

 

You are correct I believe I said it backwards. When 4wd button is "on" front driveshaft is not able to be rotated by hand (but still no power to wheels even though it sends power through the shaft. When 4wd button is "off" the front driveshaft is stationary and can be spun by hand

 

No 4lo does not work either. The gearing still changes but no 4wd green light and no power to the front wheels in 4lo or 4hi

 

Did you check 4WD fuse and 4WD position switches?

4WD fuse
Wire harness
Vehicle speed sensor
4WD position switch
4WD indicator light
Actuator assembly
A.D.D. control system
4WD control ECU
Transfer assembly

 

Yes- there is another actuator for the ADD (unless you have manual hubs). It will be on the passenger side on the stub shaft side of the front diff. Pull the harness for it and give a clean with some electric contact cleaner as a start, and then check that it's working. Be careful with both the actuators, I forget which one it is, but if you remove them incorrectly it can be a pain to get them back in sequence.

 

His actuator is working from what he said in his first post. Now maybe he was hearing the actuator on the transfer case vs the front diff.

 

That's what I was assuming.

 

Yes I believe the transfer case actuator is working properly. Not only can you hear it when 4wd button is activated but it links TC to front driveshaft when activated. However still no power to front wheels so I believe its front diff actuator problem. Going to try to run through the list you gave me today

 

So I checked all of the fuses. All look good

 

Check the switches and what andy mentioned above. Easiest to rule out.

For the actuator -
https://www.markofshame.com/fsm/03_Tacoma/Repair_Manual/03tacoma/tr/ot24ssy/insp.pdf

 

I think this points to your ADD actuator not engaging. Put it in 4x4, and jack up the front end. Spin one of the wheels and see if the other side spins too. If not, ADD is not engaged.