4X4 won't engage when cold

[torque]

It's that time of year again, I know I'm a crybaby in Calif. but when the temps are in the 50's forget the 4X4 when I leave in the morning. It clicks but doesn't engage. When the truck is thoroughly warmed up the 4X4 engages normally. It's fine when the weather is over 60.
If I let it try to engage for 30 seconds or so, the display says 'Service 4X4". That goes away if I switch the display from mileage to fuel economy.
Anybody seen this?

Torque

[AKMark]

Could be 1 of 2 things, but I'd guess it's probably the 1st.

1. Front axle actuator. Takes only a few minutes to install. I just did mine at -40 and it was easy. Unplug, untwist, get new one, twist in, plug in. Done

2. Front axle diff fluid. Considering the problem doesn't go away till it's above 60, I'm guessing #1 is your culprit.

To confirm, remove the actuator (passenger side of front axle, look at the differential, and you seriously cannot miss it) plug it back in and see if it moves when you shift into 4x4 with the ignition on.

[More Power]

It can take a little time for the various gears and splines to mesh. Cold gears and lube add to the time it can take for that to happen. To help the 4WD systems engage, usually I hit the button just before I do a 3-point turn in my driveway (or parking lot, etc). Forward/reverse helps the gears engage by taking whatever preload there might be out of the driveline. Jim

[EdHale]

I use my 4WD whenever I am on a gravel road or wet road for a few minutes. I don't make sharp turns, just pretty much straight line driving, but in and out of 4WD several times. I also use 4WD Low whenever I am on gravel or dirt. I might drive a mile or more depending on the road. I do this frequently. I don't know if it helps or not, but I have never had a problem getting into or out of 4WD.