first thing to do is locate and mark the 2 vacuum lines at the cad, so you can remove/reinstall them and not get them mixed up. you should have strong vac on one line in 2wd and the other in 4wd. this is necessary to push the diaphragm back and forth, which moves the fork, which moves the collar.

second thing to do is soak the 4 dinky little CAD bolts with PB Blaster or other penetrating oil. Do this a lot for a day or two to try and prevent the bolts from breaking.

next - with PASSENGER side only front tire jacked up, crank the truck and shift t-case to 2wd and verify the 4wd light is off. try to rotate passenger tire by hand. its supposed to rotate freely. if it doesn't, it proves the CAD is still engaged.

if this is the problem - and since your 4wd is working - decide whether you want to mess with this or not. if the CAD bolts break, your truck will be down until you can drill them out and fix it. not ideal in the middle of winter.

the most common problems are broken vac line, or rusty shaft inside the CAD.
don't spend a fortune on a new cad. if its broken, consider a posilok cable.

 

ok. thank you again for all the help

 

had time to crawl underneath the truck today and found a hole rotted in one of the vacuum lines. going to fix that this weekend and we'll see if the problems solved

 

moparlove >> i'm no expert , i do admire dhvaughn as a pro. i had same issue when ifirst bought mine , and did the same process . my total fix ended up being the steel line which follows the cross member to the cad flex lines was totally blocked with crud 110 lbs. pressure could not remove .. relpace with standard brake tube is what i did . just adding .

 

thats exactly where mine is rotted out. the brake type line that runs along the frame. the hole is about the length of a dime

 

i got more stuff goin on with my truck as of two days ago. we got a lot of snow here on tuesday and was driving to work. nothing weird. driving home from work, my truck started shiftin funny. i just thought my boot was hitting the brake and gas at same time so i thought nothing of it. go to work yesterday, trans was still doing it, only a bit worse. checked fluid, that was ok. i figured trans was goin so i had my friend (also a mechanic) come to my work to take my truck for a drive and diagnose it as a real mechanic. he comes back and said the truck did nothing. it shifted just fine. i drive home from work, and SURPRISE! shifts fine... so that was one deal
i was low on oil so he got more while he was out driving. not a dig deal there. he pulled a spark plug and ive never seen one worse. almost no electrode and corroded in white crap. a tune up will get done on sunday on my day off. but now as i was drivin home yesterday, my truck bogs down a shudders under harder than light acceleration. i called him and he said it might be the tune up. but he also screwed with some vacuum lines yesterday so i dont really know whats goin on.
sorry for the long write up. if anyone has any insight, it would be appreciated although no work can get done til sunday. and the t-case problem has been solved.

 

Man Just get a POSI- Lock system. Best 4x4 upgrade ever. And cap those lines. to big of a problem.

 

Have you fixed your plenum yet?

 

not yet but am planning too asap when it gets warmer out. i took the truck for a test drive today after sittin for a day and the rough idle and crap went away after it warmed up. now the trans will only screw up trying to shift into forth. itll go in, but after a bit of spazming