4×4 won't engage while truck is on the ground

I have a 2016 Toyota Tacoma TRD off-road. My four-wheel drive when engaged was just flashing. I have changed the actuator and actually was given a brand new transfer case. While the truck is on the lift it engages in four-wheel drive just fine. When the truck is on the ground under its own weight and you're driving and trying to engage four-wheel drive it just flashes like it did before. I'm kind of at a loss of where to go from here. Any help or guidance would be greatly appreciated.

 

Not that this is a fix but have you tried in neutral?

 

did you roll the truck forward or backward a little to get it to engage? It won't always do it when you're not moving.

 

Yes I have

 

Yes

 

Did you change the solenoids on the ADD? Could be a weak solenoid, engages when there is no resistance on lift, does not when shifting under a load when moving.

 

What surfaces have you tried on? It shouldn’t matter as mine goes engages on dry pavement, but it will add a bit more information.

 

All different surfaces

 

Replacing that now, We will see what happens

 

When you say actuator, do you mean the front diff actuator was changed or the actuator on the t-case? I understand you installed a different t-case but not sure if you moved over your old t-case actuator and replaced the front, or if the new t-case came with an actuator and you replaced the front, or if you haven't touched the front and you put a new actuator on the new t-case.

Just wanting to clarify, it will help with what to suggest. The best way to go from 2WD to 4WD is with the truck driving down the road, so you're trying in the best scenario currently at least.

 

Did this problem just start, or do you think it is tied to your offroad excursion last year, where you had an issue with lights going off?
Go back to where/when the problem started, and see what changed.

 

I replaced the actuator onto the new T- case that I have. After that did not solve the problem I changed The front actuator as well and now all is good.

 

Thanks to all that answered, it ended up being the front actuator solenoid was weak and needed to be replaced as well. Everything is working perfectly again I appreciate all answers.

 

I think that’s the new Send-It safety feature. Have to send it off a jump before it will engage. Just kidding. Solenoid is my thought as well. Does it engage when on the ground and not moving?

 

Day late and 20 cents short. As I was replying you posted it was fixed. Glad you got it sorted.

 

Good deal!

 

I win.