pull down glovbox theres a bunck of diff colored hoses red orange green ect the grey one runs to a pump on the heater box plug it

 

evader68, you still could have other vacuum leaks. If you have a vacuum gauge, you could hook it up inline at the front axle engagement actuator and see if you get the same vacuum level as you do at the vacuum reservoir. Then compare that value with the vacuum found at the engine itself. They all should be about the same.

 

i dont have a resivoir its pugged off does the actuater stay pull in all the way when 4x4 is engaged its sucking the cable as far as it can cause when its in iv tried to sqeeze it further and it doesnt budge

swartllk im almost sure the problem lies in the fron end when i push any of my buttons the autuater has a reation 2hi 4hi or 4lo 4hi 4lo its in 2hi its out

is it possible for the transfer case to not be fully engaging like maybe the electric motor not engaging the transfer case into gear all the way and its popping out of 4x4

ok here what i recently checked 4hi driveshaft wont spin, 2hi driveshaft spins, 4hi whith actuator unpluged still doesnt spin from my research this means transfer case is locking in front diff is not oh and when in 4hi and pops out shaft still doesnt spin lol could it be the collar or shift fork

 

To figure out if the problem lies in the front end or in the transfer case, try jacking one front wheel off the ground and supporting the truck so that the wheel remains off the ground. Start the engine and engage the 4wd, leaving the transmission in neutral. Then try to spin that one tire. If you can spin the front tire and the front driveshaft does not spin, then the front end is not engaged. If you you can spin the front tire and the front driveshaft does spin, then the transfer case is not engaged. If you cannot spin the front tire, both are engaged and you can now scratch your head.

Also, please do not post repetitively like that. Forum rules and all. Use the edit feature to add information if another member has not yet replied.

*EDIT* - For instance, your last reply just before mine so I didn't see where you tested some this already... You still haven't tested to see if the front axle is engaging, only that the transfer case is. Another way to look at it is to put the transfer case in 2HI and apply engine vacuum to the actuator under the battery. If you can still spin the front driveshaft, then there most definitely is a problem with the engagement mechanism inside the front axle.

 

ok sorry and thanks for the tips on posting ill lift it up 2mro and see if the wheel spins which i beleive it will cause it engages for about ten feet or when load is aplied also ill lift it up after it pops out to see what happens

 

Is your vacuum reservoir intact and check valve functional? If not, the drop in vacuum pressure from when you open the throttle could cause the actuator to release the cable and disengage the front axle.

 

no the resivoir was never there when i got it wheres the check valve ill check it lol

 

The vacuum source is the engine. The vacuum line plugs in near where the PCV hose connects to the intake manifold. From there, it runs over to near the brake booster where you will have a check valve that is also a 't'. From that 't', one line will either run to the switch on the transfer case or into the firewall to the hvac system. The other line will run to another 't' which will run to the hvac or tc vacuum switch (which ever wasn't connected to the first branch off the check valve 't') and the other will run into the vacuum reservoir which on the 98+ trucks is located inside the driver side fender.

 

do you have a picture of the vac reservoir or could you tell me how to get access to it? I'm troubleshooting the same thing

 

CLICK HERE - found using the search feature with the term as "vacuum+reservoir+fender"...