4wd flashing and not locking in help

I have spent countless hours on here researching what to do with my tundra but I am lost and looking for help from people who have had a similar issue.

I have a 2013 tundra crewmax and just recently my 4wd wouldn’t lock in. Switch in cab will make the 4hi flash on the dash but won’t lock in. Tried 4lo and truck seemed to almost lock in half way and traction control light came on dash. 4lo light wouldn’t come on dash and 4hi light continued to flash. Removed 4hi part of transfer case actuator and motor is clean, no rust. All contacts and insides look brand new. Pushed the rod back into the transfer case and reassembled gears / contacts and lights came off dash.

I then decided to replace the front diff actuator and replaced with fluid and still nothing. 4hi will just flash on the dash and will not lock in. With engine off and electrical on, when switch is moved from 2wd to 4hi, I can hear the actuator motor spinning and what sounds like the rod moving. I have spent lots of time on forums to ensure that I put the actuator back together properly.

I have also tried the “dealer trick” of full locking the wheels forward or reverse and 4hi just flashes and will not lock in.

I am now lost and looking for any suggestions on what else I could try and look for before caving and bringing it into a shop and having to pay someone. Thanks in advance

 

How fast are you going when engaging in 4WD?

 

I have tried everything from neutral, no gas / coasting and up to around 40km/hr. Dry ground, snow, rain. I did first notice this issue when our temperatures dropped to around -15 and lots of snow on the ground. But now it has warmed up, dry ground and still the same issue

 

You replaced this right

 

Yes I put in a brand new front diff actuator. Drained and replaced fluid in front diff

 

And the transfer case actuator?

 

I did not see a need to replace transfer case actuator. I opened up the 4hi side (top) with it still attached to transfer case to check if the vent hose was making the Motor and insides rust. Actuator looked brand new inside and travel path of contacts were all perfect. Gears did fall and I had to look at forums to ensure it was put back together properly. With engine not running and if I switch over to 4hi inside cab, you can hear the transfercase actuator motor spinning

 

Did you read this yet?

 

Yes I have went through that write up. Hearing the “whirring” of the tcase actuator is what led me to replacing my front diff actuator. Still did not work. I have checked all wiring and abs lines and all seem to be connected without damage