I have a 1994 gmc 4x4 and the front axles wont engage

If the actuator is not working and you need to engage your 4x4 to get home, you can manually lock in your 4x4 system using the front axle's manual locking hubs (assuming your vehicle has manual locking hubs). Here are the steps to manually lock in your 4x4 system:

1. Locate the manual locking hubs on the front wheels of your vehicle. They are typically located at the center of the wheel hub, and will have a dial or lever that you can turn or pull to engage the hub.
2. Make sure your vehicle is in neutral, with the parking brake engaged.
3. Turn the dial or lever on each manual locking hub to the "lock" position. This will physically engage the front axle, allowing power to be transferred to the front wheels.
4. Engage your 4x4 by shifting the transfer case lever into the appropriate 4x4 mode (4-Hi or 4-Lo).
5. Test your 4x4 by driving slowly in a straight line. If you hear any grinding or feel any vibrations, stop immediately and check your manual locking hubs and 4x4 system.

It's important to note that driving in 4x4 mode on dry pavement can cause damage to your drivetrain, so be sure to disengage your 4x4 system and unlock your manual locking hubs once you're back on solid ground.

That truck did not use a vacuum actuator, it used an electric motor motor. If your transfer case is engaging and you can see the front drive line spinning, then you either have a bad actuator, switch, or the wiring is bad. I would recommend unplugging your actuator and checking for power at the wire while someone puts the truck in four wheel drive. If there is power going to it, then replace your actuator. if not, follow your wiring back and check all components. They also sell an aftermarket cable actuator for those trucks which are much more reliable.

If you have locked hub drive in the front end then that shaft will be turning all the time when moving as the front wheels will be making it turn through the diff,. If you have free wheeling hubs that allow you to disengage the hubs then the shaft will be turned from engagement from the transfere case. In that case check that you are in fact changing out of 4 wheel drive and the actuator is not jammed or rusted in the engaged position

Could be the servo on the front diff not activating. Could be a power prob or failed unit.

2002 chevy s10 4 door 4x4 4 wheel drive wont engage

u may have a lock hub failing 2 engage on front axles.if u have autolockers they have been knowen 2 seize up.some times a strip down&clean out®rease will sort them out also check the front jack shalft from transfer box 2 front diff make sure not lose or play in unijoints

my computer problem is hard disk system found warantty hard disk

actually that first soultion is wrong it is correct on smaller pickups but on the full size pick ups they use a differnet sytem
there a electric actuator on front axle
there be two elctrical plugs on front axle u want the bigger of the two other one is just to turn the 4 wheel drive light on
un plug actuator then remove actuator after it removed plug it back in but leave it out of axle turn key on and shift down to 4 wheel drive the actuator should move out if it dont that your problem if i does move this isnt your problem it either the tranfer case or in front axle

if you look there is probably only one axle shaft turning also that shaft should not turn unless the wheels are there is probably something wrong with that hub not a big problem to tear down and check you can also get replacement hubs that are manual locking.

the front diff. is engeged by a thermal acuator in the front center section. check that the wiring on the pass. side of the front axle is of, if so the the acuator is probably faulty. Best to get an aftermarket posi-locking shifter if you need to replace the thermal unit.