Front wheel gear not engaging

did you turn the locks on the wheels, or check the fuses

I am thinking that you have a broken/ stripped drive spline on a front axle. If you have reduction gears in the hubs , it may be stripped teeth on a gear. If you jack up one front wheel and turn the drive shaft that wheel should turn. IF so repeat the procedure for the other wheel and if it doesn't turn like the other side then that is the side with the problem

yes replace

The Selectable Four Wheel Drive (S4WD) Front Axle consist of the following components:
• Differential Carrier Housing
• Differential Case Assembly
• Inner Axle Shaft
• Intermediate Shaft Bearing Assembly (located on the right side of the oil pan)
• Electric Motor Actuator
The front axle on Selectable Four Wheel Drive (S4WD) model vehicles uses a disconnect feature mounted on the right side of the oil pan in order to engage and disengage the front axle. When the driver engages the 4WD system, the Transfer Case Control Module sends a signal to the electric motor actuator to energize and extend the plunger inside. The extended plunger moves the clutch fork and clutch fork sleeve across from the clutch fork outer gear that is splined to the right side wheel drive shaft to the clutch fork inner gear that is splined to the inner axle shaft. The locking of the two gears allows the axle to operate in the same manner as a semi-floating rear axle. A propeller shaft connects the transfer case to the front axle. The differential carrier assembly uses a conventional ring and pinion gear set to transmit the driving force of the engine to the wheels. The open differential allows the wheels to turn at different rates of speed while the axle continues to transmit the driving force. This prevents tire scuffing when going around corners and premature wear on internal axle parts. The ring and pinion set and the differential are contained within the carrier. The axle identification number is located on top of the differential carrier assembly or on a label on the bottom of the right half of differential carrier assembly. The wheel drive shafts are completely flexible assemblies consisting of inner and outer constant velocity CV joints protected by thermoplastic boots and connected by a wheel drive shaft.

How To Install Repair Replace 4x4 Front Axle Actuator Chevy Trailblazer...

If I read this correctly ( which I might not have, bit early for me ), the front drive shaft will engage ( from the transfer case ) but the front wheels are not engaged ?

If so, sounds like either the vacuum from the IWE ( Integrated Wheel End ) is not being released, or the IWEs have had an issue with part vacuum ( damage vacuum lines ) and the IWE gear is rounded off.

If you pull the vacuum lines at the IWEs ( there are 2 lines, 1 is the vacuum line, the other is the vent tube that routes up into the engine compartment and is not attached to anything ), the front wheel should engage ( might need a 5 * turn to mesh the gears ). With the vacuum lines off, jack up the front axle ( take precautions, chock the rear wheels, parking brake, jack stands, etc ) see if the front wheels are engaged ( turning one wheel should turn the other ). The option is to do this after the truck has sat over night, and the vacuum has been released out of the vacuum reservoir.

If the wheels turn correctly ( engaged ) I would think the contact plates in the transfer case are not making contact. Good starting point for this is the connector on the side of the transfer case, some times this gets gummed up, and the pins do not make good contact. The contact plates in the transfer case are used for a few things, one of them is to signal the IWE solenoids to release vacuum to the IWEs.

Operationally vacuum holds the IWE ( Integrated Wheel Ends ) out, and once vacuum is removed the spring engages the IWE.

Here is a black diagram of the IWE vacuum system

SOUNDS LIKE A BAD HUB TRY THIS TO DIAGNOSE THE PROBLEM

Put the transmission in park, set the parking brake and raise the chassis so one of the front wheels is off the ground while the other is still on the ground. When the transfer case is in two-wheel drive, the hubs should be released allowing the wheels to turn freely when spun by hand. If the axle shaft turns when you spin the wheel, it means the hub has not disengaged.
To check engagement, rotate the axle shaft backwards. This should lock the hub. Try turning the wheel by hand again. The axle shaft should now turn with the wheel if the hub is locked. If the hub fails to lock, the hub will have to be disassembled and inspected or replaced.
To check release, hold the axle shaft steady and rotate the wheel backwards. You should hear a click as the locking mechanism slides back out and disengages the hub. Rotate the wheel forward again and it should turn freely.
Another way to check the hubs is to raise the vehicle on a frame contact lift so all four wheels are off the ground. Then start the engine and place the transfer case in four-wheel drive and the transmission in drive. If the front wheels don't turn, look at the front axle shafts. If both shafts are turning, but one wheel is not, the problem is a bad hub on the wheel that isn't turning. If the front driveshafts are not turning when the transfer case is in four-wheel drive, the problem is inside the differential (broken side gears) or the transfer case (broken chain, shift linkage, etc.). If the driveshaft between the transfer case and differential is turning, the problem is in the differential. If the driveshaft is not turning, the vehicle is going to need repairs to the transfer case.
Hope this helps.

The alignment angles may off due to worn parts. The half shafts on the Maxima might be worn, as indicated by a clicking noise on turns. The camber and toe can be off caused by worn ball joints or tie rod ends ( which are connected to the rack and pinion), respectively, causing the wheels to appear to be 'toe out' as you describe in your problem.

Sometimes, the wheels will appear to be toe out compared to the body, but are in reality dead straight ahead according to the alignment machine which can measure angles down to a fraction of a degree.

Are you experiencing irregular tire wear, indicating poor alignment?

Before a computerized alignment can be performed, the front end parts should be tight for the various angles, including cast, camber, and toe.

The axles, are less of an issue, except worn ones can cause that notorious clicking and eventually lead to a break down in the drivetrain where the half shaft joint actualy breaks apart.

Also, a worn axle can cause the bearings in the hub to go bad if the axle is binding at all.

It's a good idea to have all of the front end parts as tight as possible.

On your model I beleive these wheels are driven with small gears inside the inside diameter of the wheels. If the shaft is turning, then you probably have a gear problem. Remove a wheel and inspect both the wheel, and the small gear. They are prone to wear.I'd suggest replacing all four parts if worn.

I have a Craftsman self-propelled lawn mover on which the right-side front wheel will not turn when the belt is engaged. I removed the wheel and found that the plastic gear teeth on the inside diameter of the wheel were worn down. The metal gear on the shaft is still in good shape. This has happened before, and the fix was to replace the wheel.

diff unit broke ,drive shaft broke or engaging solonoid not working