4x4 slips in and out.
 

hay there, i have 97 12 valve ext cab, long box, 4x4. it doesent seem to go in 4x4, at first but when you start to spin you can hear a grinding noise, then it will go in with a glunk. it will slip back out. i hade the actuator off, it seems to work when its off.lots of vacum.at least 30in. any ideas would be helpfull. snow is starting. thanks.

Did ya check the vacuum lines going to right side of the front oil if ya got a leak or rust down in one of those lines or fittings then it no work:pca1::pca1:

Ever had the trans or t-case out? When my trans was installed the T-case linkage was tuned upside down on the install causing it to rub the t-case and it would jump out of 4wd.

I dont know about the t case, but i will check it out. vacume lines look good.

t-case = transfer case just wanted to clear that up

Is it coming out of 4x from the transfercase or is the front axle disconnect letting go? Big difference in the two. If the front disconnect is letting go then make sure that you have vacuum there all the time and if you do then it's most likely the actuator itself. You can buy a cable actuator for it if you want of if you're any good at mild fabs you can use a throttle or choke cable off a lawn mower to actuate it.