2017 TRD Off Road won't engage 4Lo or lock rear diff

I'll give it a go and report back

 

Either the plunger isn't moving or the the indicator switch isn't working. Push the button, drive a bit while steering some, and then physically check and see if the diff is locked. If it's not locked then the actuation system/dog clutch/plunger isn't working and if it is locked it's just the indicator switch.

 

How will I be able to indicate it's locked by just looking @ it?

Also, wouldn't I hear a small clunk the same way you do when you put it in 4wd?

 

If you don't know how a locked rear drives over terrain then you'll need to jack the truck up and check.

The locker is capable of engaging cleanly without any clunk.

 

I know it's supposed to skid while turning because the wheels are moving at the same rotational speed, but doesn't it do that even while it's in 4LO?

 

There's still differentiation across the axle in low range when the diff is open. You can observe this while crawling when the truck loses traction at a rear wheel or lifts a tire. When turning there is also more total bind across the rear when the diff is locked in 4LO vs diff open in 4LO.

Easiest thing to do is put the truck on jack stands and troubleshoot it in the garage.

 

Tracking. Thanks mane