i have a 99 dodge ram 1500 and the 4wd is kicking out, originally i had a broken vacuum line which was why it was kicking out so i temporarily taped it till i had money to replace the lines, then the 4wd stopped all together so i changed the 4wd vacuum lines and still nothing so i changed the 4wd vacuum actuator on the front diff and now i have 4wd but it slips, anyone have ne idea what this might be?

 

Check to make sure you installed the shift fork in the right direction on your actuator. Did it work immediately after replacing the CAD or did it take a while before it started slipping again? Also, clarify what you mean by "slip"

 

yeah the shift fork is the right direction, i changed out the hole fork/actuator assembly and the 4wd worked right away but when i drive it willkick out of 4wd and then kick back in

 

Check your linkage on your t-case and make sure it is set-up correctly. Maybe it's not engaging all the way.

 

i dont think that would be it because when the vacuum line broke if i put it in 4low then i would get the low gearing in 2wd and it wouldnt slip, but ill take a look maybe something moved from it kicking in and out when i had the line taped

 

yeah i checked the transfer case linkage and it wasnt that. i think ill try getting rid of the vacuum actuator and get a posi lock instead and hopefully that will fix it

 

I would look at yourCAD unit, take it off and see if the splines on the intermediate shaft are worn, I had this same problem, the shift collar kep't slipping when in 4*4, also if thats not it. I would check your spider gears in your front diff. If there is a broken tooth on the spider gears it will act like its comimg in and out of 4 wheel drive.