My transfer case is not working to change it to 4WD?

This is hard to know for sure but we need to start with listening to see if the actuator is trying to engage. If it is not then we need to check for power at the actuator and if there is power then the actuator needs to be replaced.

https://www.2carpros.com/articles/how-to-check-wiring

The most common cause of this is the actuator so I attached the process below on how to replace this. Please let us know if you have questions on this. Thanks

Hello,

This happens when the transfer case shift actuator/sensor needs to be replaced. Here is how you fix the problem:

Note: New shift motor assemblies are shipped in the 2WD/AWD position. If a new shift motor assembly must be installed, it will be necessary to shift the transfer case to the 2WD/AWD position prior to motor installation.

Raise the vehicle on a suitable hoist.
Disengage the wiring connector from the shift motor and mode sensor assembly.

Remove the bolts (3) holding the shift motor and mode sensor assembly (2) onto the transfer case (1).
Separate the shift motor and mode sensor assembly (2) from the transfer case (1).

Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

Cheers, Ken

Good evening,

It sounds like one of the axles are not locking in.

Is there any damage to the axle? Is it turning?

Roy

C205F - Front Axle
DESCRIPTION
The C205F axle consists of an aluminum center section with an axle tube extending from one side. The tube is pressed into the differential housing. The power is transferred from the axle through two constant velocity (C/V) drive shafts to the wheel hubs. The drive shafts are identical and interchangeable.

The differential case is a one-piece design. The differential pinion mate shaft is retained with a rollpin. Differential bearing preload and ring gear backlash is adjusted by the use of select shims. The shims are located between the differential bearing cups and the axle housing. Pinion bearing preload is set and maintained by the use of a collapsible spacer. The differential cover provides a means for inspection and service.

The axle has the assembly date and gear ratio listed on a tag. The tag is attached to the housing cover by a cover bolt.

OPERATION
The axle receives power from the transfer case through the front propeller shaft. The front propeller shaft is connected to the pinion gear, which rotates the differential through the gear mesh with the ring gear bolted to the differential case. The engine power is transmitted to the axle shafts through the pinion mate and side gears. The side gears are splined to the axle shafts.

Okay, if it does not turn, then you have a defect inside the front differential.

It will have to be opened up to inspect for the failure.

Roy

Did you check to see if there is power to the actuator on the transfer case when you turn the swutch?

If there is power to the switch, check the relay under the hood in the power distribution box. Make sure there is power to it and switch it out with a different relay in the box with the same part number to see if that makes it work. If there is no power to the relay, we have to work backwards to the switch unless there is no power there either.

More then likely this is due to the shift motor has failed. I attached the process below that will help replace this.

The fact that is it grinding shows that the motor is trying to shift which proves out all wiring and the switch which leaves the motor or the transfer case itself. Which is more likely to be the motor and not the case.

Below you will find the process on how to replace this shift motor.

Let me know if you have questions on this and we can go from there.

I think you are correct. THere is a switch on the top (of all places) of the transfer case that turns the light in. They go bad. The part just unbolts, but it is a tight space.

Here is what I was able to find. I believe you need to locate the mode sensor. Confirm that with the parts store. NOTE: This picture is for a 6 cylinder auto trans.

Based on what you described, it sounds like the linkage has slipped. Check the linkage under the truck. Note what direction it moves for the 4wd positions, and then loosten the linkage and move the transfer shifter by had to the different positions. Once you determing it's in a specific gear, place the shifter in the same position and tighten the linkage.

Let me know if this helps.

Joe

Hi,

The system is actuated via engine vacuum. Do me a favor. Crawl under the vehicle and look up at the transfer case. Check for broken, disconnected, or dry rotted vacuum hoses.

Next, it has been some time, but I believe there is a vacuum reservoir under it as well. It will be black plastic and round. Check that as well.

Finally, the vacuum hoses run to the front axle. Check there as well.

I attached the only pic I could find related to the vacuum/4wd. It will help you locate the vacuum switch on the top of the transfer case. Keep in mind you have to make sure there is vacuum getting to the switch from the engine.

Let me know what you find or if you have other questions.

Take care and God Bless,

Joe