hey guys...

the cad unit on the front axle of my truck is not fuctioning therefore i cannot use my 4wd... can u get a replacment unit at a napa or local parts store like that or do u have to go through dodge? if anybody knows please let me know... thanks in advance, later

 

HI, You sure it's unit itself? Have you checked the vacuum lines that operate the CAD unit for leaks? Just a thought.

 

Instead of tracking down the problem with mine knowing the cost of the CAD vac motor alone I replaced the flawed system with a POSI-LOCK. Even in perfect condition the system has problems engaging in cold weather & since 50% of my 4x4 use is in the snow the cable replacement was the best way to go.

 

I replaced with posi-lok as well. Check it out. Do a search on here, people ask about it almost weekly it seems. The real popular ones end up turning up a LOT of info to sort through, but see what you can do and if you still have q's, come back and we'll see if we can figure out your problem.

 

i would go with the posi lok. but to answer your question advance can get them through the dealership i believe.

 

if your interest in keeping a cad - if your vac lines are good and the cad is still not working, you can probably disassemble the cad and fix it. there's not much to them and its often a stuck or rusty shaft or something.

don't assume its not working just because the lights not on. if 4wd engages you will feel a lot of binding in a tight turn.

beware a new cad will probably cost moren tha a posi-lok. a junkyard would be the cheapest place to get a replacement cad.

i recommend posi-lok and throw the damn cad away.
https://dodgeforum.com/m_718119/tm.htm

 

yea i checked all the lines visually and did a vac test on lines from the tcase and tested the actual cad unit... i also took the unit off and played with it makin sure it wasnt sticking and it was fine... but im def going to check out that posi lock a little more, how does that red button thing work?

 

the red **** pushes/pulls the cable which is directly attach to the shift fork. the **** has a center button that releases a catch and allows you to move the ****. when you let go of the center button, the **** and cable lock in that position.

so when you push the **** all the way in, the axle uncouples. when you pull it all the way out (about 1-1/2 to 2"), the axle couples. this manually duplicates what your cad does.

that's only half the action. in addition to that you shift the t-case. so the t-case gives you 2hi, 4hi, 4lo. both the 4wd settings turn the front drive shaft, but you don't actually get front drive until you pull the posi-lok **** to couple the axle. otherwise you simply turn the spider gears and the inner half shaft.

so when its all working together you have 6 possible setting, but only 4 viable options.
2hi. posi-lok disengaged. this gives normal 2wd, high range.
2hi. posi-lok engaged. same as above, a few more parts rotate in the front, but you don't gain anything. (insignificant setting)

4hi. posi-lok disengaged. front drive shaft turns, but no 4wd. (insignificant setting)
4hi. posi-lok engaged. normal 2wd, high range. (same as what your cad does).
4lo. posi-lok engaged. normal 4wd, low range. (same as cad).
4lo. posi-lok disengaged. low range, 2wd !! great for slow speed trail riding, easing around the yard, include sharp turns, which 4wd doesn't do very well.

 

o thanks man that was really helpful