My 4WD will not engage why?

Hi:
I need you to check the linkage to the transfer case to make sure it's working properly. Also, check all vacumn lines to and from the transfer case, axle.

Check to see if there is vacuum at the cut hose. If so, replace it.

I would go back to the tranny installer and see if the misadjusted anything. The only thing you can do without disassembly is adjust the shift linkage. Here's how:
SHIFT LINKAGE 1. Move shift lever to 2H position. Raise and support vehicle. Loosen shift rod lock bolt at trunnion on linkage. Ensure shift rod does not bind in linkage trunnion. Re-check that transfer case shift lever is in 2H position (second position from full forward). 2. Lower vehicle. Position shift lever in cab so distance from instrument panel to 2H position dot in shift lever insert in 5.75" (146 mm). Ensure measurement is made parallel to floor of vehicle. Tighten shift rod lock bolt to 90 INCH lbs. (10 N.M). Check shift and linkage operation in all ranges. Readjust as needed.
WILL NOT SHIFT OR DIFFICULT TO SHIFT INTO GEAR Vehicle speed too high; slow vehicle and attempt shift. Vehicle has been operated in 4H mode too long on dry surface; stop vehicle, place transfer case in Neutral to relieve driveline preload torque. Ensure transfer case external linkage is not binding. Ensure correct fluid is used. Internal parts may be worn or damaged.

Heres the vacuum diagram for the t-case controls.Be sure it is all hooked up properly

Hello,

It sounds like the shift fork bushings have worn not moving the fork completely. Here is an exploded diagram so you can see what I am talking about. I would see if you can manually move the shift arms to see if you can get it to work. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

When you have it apart look at both forks I would replace all plastic ride retainers if they look worn or brittle. Can you please shoot a quick video with your phone so we can see what's going on, that would be great. You can upload it here with your response.

Is the light indicating at 4WD? Scan the TCM/Computer for code/s if any present post them-

Check vacuum at axle shift motor

AXLE SHIFT MOTOR FUNCTIONAL TEST
Raise and support the vehicle. Disconnect the vacuum harness from the axle shift motor and connect a vacuum pump to the vacuum shift motor front port. See Fig. 2.
Apply 15 in. Hg (51 kPa) of vacuum to the front port and rotate left front wheel to fully disengage the inner and intermediate axle shafts (i.E, shift to two-wheel drive operation).
The shift motor should maintain the vacuum applied to the front port for a minimum of 30 seconds. If the motor does not maintain the vacuum, replace it. If the motor does maintain the vacuum, proceed to the next step.
Disconnect the vacuum pump from the vacuum shift motor front port. Connect the vacuum pump to the vacuum shift motor rear port, cap the port for the 4WD indicator lamp switch, apply 15 in. Hg (51 kPa) of vacuum to the rear port.
The shift motor should maintain the vacuum applied to the rear port for a minimum of 30 seconds. If the shift motor does not maintain the vacuum, replace it. See AXLE SHIFT MOTOR under REMOVAL & INSTALLATION. If the motor does maintain the vacuum, proceed to the next step.
Remove the cap from the port for the 4WD indicator lamp switch. If vacuum was present, the shift motor is functioning normally. If vacuum was not present, go to next step.
Apply 15 in. Hg (51 kPa) of vacuum to the shift motor rear port. Rotate the left front wheel as necessary and ensure that the inner and intermediate axle shafts are completely engaged. The axles must be completely engaged (i.E, shifted to 4WD operation) to open the port for the 4WD indicator lamp switch.
Determine if vacuum is present at the port for the 4WD indicator lamp switch again. If vacuum was present at the port, the shift motor is functioning normally. If vacuum was not present at the port, replace the shift motor. See AXLE SHIFT MOTOR under REMOVAL & INSTALLATION.
Connect the vacuum harness to the shift motor. See VACUUM HOSE ROUTING. Remove the supports and lower the vehicle.

You should have shift on the fly 4wd. That means you can shift into 4wd when you are moving at a slower speed. You can take it out of 4wd the same way.

As far as the noise, that is normal. You hear the transfer case and the front differential being engaged. Nothing to worry about.

Now for the hop you experience. DO NOT USE 4wd on a dry surface where the tires can get good traction. If you do, the steering will fight you, it will hop, and eventually cause damage to the 4wd system. Only use it when the conditions justify it such as snow, ice, mud, any condition that would allow the tires to spin.

Let me know if you have other specific questions.

Joe

Hi and thanks for using 2CarPros.

Most often, the shift linkage between the shifter and the transfer case either comes apart or comes loose and goes out of adjustment. That is where I would recommend you start.

Park on a level surface, place the parking brake on, place the vehicle in park, and block the wheels so the vehicle can't move. Craw under the vehicle and locate the transfer case. Locate the linkage (see picture 1) and conform that it hasn't come disconnected on either end (held in with a plastic clip on both ends) and make sure the adjuster bolt didn't come loose allowing the linkage to move without changing the transfer case shift lever.

If you find the linkage has come off, you can purchase just the plastic clips or you can purchase the entire linkage aftermarket.

Here are the adjustment directions:

______________________________________________________

ADJUSTMENTS
1. Move shift lever into 2H position.
2. Raise vehicle.

3. Loosen shift rod lock bolt at trunnion.
4. Check shift rod fit in trunnion. Be sure rod does not bind in trunnion.

5. Verify that transfer case shift lever is in 2H position.
6. Tighten shift rod lock bolt to 10 Nm (90 inch lbs.) Torque.
7. Lower vehicle.
8. Check shift linkage operation. Be sure transfer case shifts into and operates properly in all ranges.

_____________________________________________________

Let me know if this helps or if you have other questions.

Take care,
Joe

The transfer case actuator motor should fix the problem here is a diagram below to show you how to replace it.