There are things to check before going that route. Did this problem just show up? It could be a bad actuator or switch on the transfer case. Easy fixes if your willing to try.

 

Been trying to locate issue off and on for year now. Had it to a friend's garage. Seems as actuator is working. When up on lift front wheels are locked in but no power to them when in drive.

 

Try this, with the truck in drive creep forward and engage 4H. Stop and shut off engine while in drive and 4H. Shift to neutral or park and restart truck. Creep forward again and turn the wheel in one direction. If you "feel" that resistance of 4 wheel drive you most likely have a bad 2/4 switch on the transfer case.Using this method I was able to restore my truck to functional 4 wheel drive twice by replaceing that switch.

 

Ok. Very helpful haven't been advised to try that. Thanks I will try it shortly

 

Ok. Tried that sequence but still not in 4wd. No resistance and rear wheels spin.

 

Is it possible the actuator is not turning enough to fully engage and lock in front axle?

 

The way to tell is to see if your front driveshaft spins freely after you've engaged 4wd.

If you engaged 4wd the front driveshaft shouldn't turn by hand.

You'll may have to remove the actuator and use a long ratchet extension to push the shift fork manually. You'll need to safely raise the front of the truck so you can turn the tires to line up the shift collar splines.

While you have the actuator out you can select between 2wd and 4wd to see if the actuator works properly.

Good luck brother.

 

Ok we had truck up on a lift so the front wheels shouldn't spin freely when 4wd engaged? The front actuator was removed before and checked it was operating. We wondered if transfer case actuator wasn't working properly.

 

The front wheels shouldn't free wheel while in 4wd. Actually if your front axle is engaged one front tire should spin forward while the other spins backwards when turning them by hand.

Can you hear the transfer case encoder motor working when you select between 2wd and 4wd?

If the encoder motor doesn't make any noise when you switch between 2wd and 4wd I've actually got them to work by pecking them lightly with a hammer while changing between 2wd and 4wd.

 

Transfer case causes the front driveshaft to turn. Actuator causes the front wheels to lock together. With the front end jacked up with wheels off the ground, turn the truck to the "on" position - not cranked up - and spin one of the front wheels. If one turns, but the other doesn't your actuator isn't working.

 

Oh yeah there's a shift fork in front axle that actuator engages to lock it in right

 

Ok. 4hi was engaged with ignition in on and could here encoder light flashes few times then goes solid. I actually replaced front actuator already.

 

Does the front actuator work? I had to replace some parts in the driver's side axle tube because there were some worn out bearings and seals and the actuator was not actually activating the fork and the front end was not locking correctly.

 

I'll have to check the new one to make sure it actually works then check the bearings and seal in the tube. It seems that everything else is working. I won't get to look at it til next week but thanks for all the input.

 

With the truck in "on" position and front wheels jacked up off the ground, if you can turn the driveshaft with your hand, you have a transfer case problem. If you can turn the front wheels independently from each other, you have a front axle actuator problem.

 

Ok. Very helpful to narrow down what my problem is. We'll try that. Hope to get it figured out asap as I live in central PA and snow will start flying anytime now!

 

Ok. Talked to my friend. He could move drive shaft by hand. Front wheels did not turn independently. So do I need a new transfer case then?

 

Then you have a problem with the transfer case. That's a very expensive piece of hardware unless you can find a known good one used. I'd now start looking for ways to test the actuators in the transfer case. Does the transfer case make noises like something is going on inside when you switch into 4 hi or 4 lo? If you have the key in the "on" position and press the 4x4 hi, with the door open, do you hear noise from under the truck right by the driver's door? If not, I'd check wiring to the transfer case. There's basically 2 things to check. First is the transfer case motor. I've attache a picture of it. You can actually remove this from the transfer case an shift into 4 wheel drive and see if the shaft on the motor turns. The other thing to check is the control module under the driver's seat. Here's a video for that

 

We'll have to do some more checks that you've mentioned. I can hear something moving when going to 4hi Also there's a clunk when going to 4lo

 

i had to get a new battery when it was replaced the service 4 wheel drive light came on, it will not go into 4 wheel drive

 

Did this problem just show up? It could be a bad actuator or switch on the transfer case. Easy fixes if your willing to try.

How strange, this is the exact wording I used in post #2 back in 2019.