I know this subject has probably been beat to death on here but I have not come across anyone that has the exact problem as me.

When I shift into 4x4, the light on the dash comes on and you hear the differential click and it feels like it is engaged. But, it does not. When shifted into 4 low, the light comes on and it feels like its engaged but its not. When the truck is lifted off the ground the tires don't spin.

I had a shop tell me it was going to be $1500+ to get fixed but I just have a hard time believing that. I feel like the differential is working.

Has anyone had this same issue?
Any help would be awesome.

 

I'm guessing the shop told you more than just the price...what were their findings?

 

Have you read the first sticky on this page to get some knowledge?
The light coming on is only telling you the electrical circuit completed, not the mechanical lockup the Actuator is supposed to do at the axle..
Get under and look at the actuator for operation.
The price quote tells me the shop has no idea and is covering for it.
Good luck.

 

They did not know for 100%. The computer said it is working fine. They told me they "thought" it was the shift fork and gear.

 

When you engage 4 x 4 the first thing that happens is the transfer case motor moves a lever and engages the front drive shaft. After that the vacuum switches send vacuum to the front axle to move the small vac cylinder to engage the axle shaft to the drive shaft......... Start the truck and put it in 4 x 4.. Shut off the truck and crawl under it and try to turn the front drive shaft. It should be locked inside the transfer case to the rear end.......... If it turns, you are not connected inside the transfer case or the front differential...... next, jack both front tires an inch off the ground and try to rotate one tire by hand. If it rotates, look at the drive shaft to see if it is turning also.. If the tire turns and the drive shaft does not, then the front axle is not engaged... If the tire turns and the drive shaft turns, then the transfer case motor did not engage inside the case.

 

Additionally, there is no computer control of 4x4.
There is no computer to tell them it's fine.
Looking at the GEM module cannot tell what you described.
Sorry to counter most of what you were told by the shop but they do not know how the system works or they would know where in the sequence the failure is.
You came to ask, you got the right answers.
Good luck.

 

ok..I have gone through and done all the system checks in the above sticky. I think my solenoids are good. There is vacuum coming all the way to the actuator on my transfer case. When it switches to 4x4, the actuator does not pull the pin to go into 4x4 therefore not engaging the 4x4. Does this mean i need a new actuator? The pin connecting to the actuator seems to be tight, as I cannot put it into 4x4 manually. I can not get it to hinge at all.

 

Hose it down with some PB Blaster or whatever you like to free it up. Even with the cover on there it tends to get dirty.

 

Is there vacuum at the firewall solenoid with the running?
If yes, does solenoid operate in 4H?
If yes, does that vacuum pass through the solenoid and appear at the Actuator?
If yes, did the Actuator move to engage the axles in the housing?
If no to any of these find out why.
Good luck.

 

yes..to all of them except "did the actuator move to engage the axles in the housing". The actuator does not move when shifted from 2wd to 4hi or 4low.

 

The Actuator moves a splined sleeve inside the axle housing to lock two axle halves together.
The Actuator is frozen or faulty.
Put your 1500 in the mail please!
Good luck.

 

gat some penetrant and a 2 pound hammer. soak the actuator rod and bump it around with the hammer until it will move back and forth freely ........ with the vacuum.

 

congratulations on retaining all your BEER money !!!!!