4wd not engaging.

4wd will not engage when the truck has been driven around. The 4wd will work perfectly when activated after a cold start. I’ve replaced the front diff actuator the other day and still the same issue. Anyone dealt with this before?

 

Mismatched tires can do this.

That is:

Actually mismatched tire sizes.
New tires vs used tires.
12/32 vs 6/32
In summery, anything that makes the ft and rear driveshaft turn at different speeds.
Food For Thought.

 

Tacoma Mike my tires are pretty new and have limited mileage on them less than 10k I believe I’ve rotated them twice so the wear is pretty even amongst all of the tires.

 

Just for shits and giggles. Run that puppy down a straight road around your house around 30, throw it in neutral, wait a couple of seconds then put it in drive and try to see if it will go in.
I use to do this all the time to check the operation.
Sometimes they won’t come out and you have to get all 4=wheels off the ground and run the system to take the strain off the system.
Saw this more with older systems..

so you’re on your own doing this but you need to start somewhere.

 

Ya that’s basically what I have to do to get the 4wd to work after I’ve driven the truck a few miles. 4wd won’t engage at slow speeds or stationary. I use the truck to off-road so I can’t rely on being able to do 30 mph at the trailhead.

 

Have you tried going backwards a few lengths and then forward white it’s trying to slide in?

 

Take apart the Transfercase motor and clean it

 

Ya that was my first thing I did when it wouldn’t engage after I had the diff actuator installed.

 

I’ll see about doing that wouldn’t hurt at this point.

 

When you say won't engage you mean the 4wd light keeps blinking or nothing happens?

 

The 4wd light blinks and there is no engagement. You can hear the actuators activating under the truck.

 

Can you check the limit switch voltages at the 4wd ECU when it's acting up and post your results so we can see what isn't where it needs to be?

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Do you know if you can bench test the transfercase motor actuator with it on the tcase? I wasn’t sure what pins to apply 12v to to get the motor to go in 4hi/4lo and then back to 2hi.

 

Had something similar on my 2006. For me it was because of a water crossing with my Transfer Case actuator. Replaced that and it worked fine. Mine would also get stuck in 4wd occasionally.

 

Alright I’ll see about tearing apart the t-case actuator.

 

When you've disassembled the actuator it is *very* important to make sure it's clocked correctly during assembly.

 

I just took mine apart. I pushed the shift rod all the way in for 2wd and then when I reinstalled the motor assembly I turned it 100% counter clockwise. I think this is correct but I have no way to test it before installing the transfercase back in the truck.

 

You can, I'd have to look at the diagrams again but I think Pins 1 and 2 are the motor pins.

I'd do the limit switch voltage checks first so you know what your looking for.

 

is this referring to the sensors on top of the T-case? if so, I second this. I had a similar condition where my truck would switch into 4wd sporadically, and the more I think about it, it went in better when cold. once it warmed up it was hit or miss, usually miss, with the indicator blinking. Took apart the ADD actuator to solder the contacts, no change. replaced the sensor and now everything works perfectly.

 

It's all in the thread I posted but there's 5 limit switches (3 in the Transfer Case Actuator and 2 in the ADD Actuator) and 3 detection switches (2 on the Transfer Case Actuator and 1 in the ADD Actuator) that the 4wd ECU uses to determine the position of the actuators and the mechanical position of the Transfer Case and ADD.