Diesel_Power_2

Hello Everyone,

Got 6" of snow last night thought I'd head out in it and play but when I engaged into 4wd Only the rears were spinning But the neighbour said the front drive axle was turning but Not the front wheels? I limped back into the driveway with his help. Anyone have any idea what is happening here?

Thanks ppl.

Tate

The CAD did not engage.

casey sohc

i used to un hook the -air lines from below my transfer case to let the front diff roll in to 4x4,then plug the line with a golf tee.i had even changed the 4x4 air valve on the transfer case (i knew that wasn't the problem a new one from dodge was $20) turned out there was a cap plug on my vent line from the diff,the truck never worked properly till now,
have you owned the truck long??
does the light on the dash work?
did you have any issues before with 4x4?
that valve from hell that operates the diff is on the top of the transfer case and moisture sits up there and rots it.
it will stick and not too hard to change,there are 4 air lines into it.
i try to use my stick to engage the diff at least once a week.
good luck and let us know how it turns out.

Diesel_Power_2

Hello casey oshc,

I have owned this truck for almost 3 years now and have repaired numerous things. I had thought the 4x4 was reliable and have used it a few times in the last summer to make sure things do engage and lube as mentioned by ppl here. The light does work but usually flickers then stays on after about 30 secs or so, Not today though I "Assumed" it was engaged and almost had to call bcaa.

It has warmed up alittle now and I got it to go into 4x4 low a couple times then 4x4 high now is in. I travel alot in bad weather and I NEED to have 4x4 reliable and am seriously thinking of selling this truck as it seems to always need something.

The 2 vacuum lines that are at the diff/switch are in good condition and secured at both ends.

What/where is this cap line on the diff vent line? Maybe mine has the same issue?
Thanks for your input btw.

casey sohc

the cap on mine was on from factory,(it had a problem from new,)but it is supposed to have a filter on the end of the line (looks like a small engine fuel filter)it is in the wireing loom on the drivers side if the transmission almost to the fuel filter.(thats where mine is,and i think the line was pink or red in color.)the line i disconnected and plugged was under the T case it is a bastard to do in crappy weather where it goes to the solid metal line and i plugged the vacume(i really can't spell) line with a golf tee to keep slush out of the pump and so my brakes still worked.it sounds to me like the switch or filter is plugging,in your case the switch may be sour...moisture+cold=frozen or stuck and it's only a $20 ish part.

Don T

I installed posilock so I would never have problems getting 4x4 when I need it to work.No more vacuum I now have a wire cable to the front dif.

Tate

I have a vacuum line directly off the main line to the CAD so it is engaged at all times. I also have a NV271 t-case and manual hubs. But its something that can be considered. It would be no different than a late 2002 with a live axle.

casey sohc

with my 96 when vacuum is lost it will default to 4 wheel drive,(it will roll the front diff in.)when i would pull the vacuum line off the diff,it would lock the front in then pull the lever in the cab and you are ready to roll,a quick fix in the driveway to get through an early snowstorm.

Diesel_Power_2

Hi casey sohc,

I think your truck is close to mine in age/mileage. Question, if I pull the line and plug it with a golf tee or something the 4x4 will roll in once moving and the lever in the cab is pulled into 4x4 high? Also,do you know if the vacuum switch does anything besides light the 4x4 light inside the cab?

I will search for CAD problems here to try to understand how it engages.

Thanks casey and everyone for the input/advice.

TxDiesel007

times two..

posilock it and forget about it..

casey sohc

once the line is opened with the lack of vacuum you will hear a puft! of air the diff may make a noise or may not,mine did sometimes.the 4x4 lite will stay lit on the dash all it does it tell you the diff is rolled in.so with the diff engaged the transfer case can be placed in 4 hi or lo as needed.dartmouth dodge told me about the switch issue,and mine was a bit rusty but i replaced it then threw the other away so i wouldnt try to use it over(it would be like the headlamp with low beam burnt out that dad kept on the shelf of the garage...just in case..)
here is how the diff works the shift fork slides this collar to the left to engage the diff




2 wd collar to left


4x4 collar engages both shafts.

infidel

Homemade Posi-Loc for $30 http://www.jeepforum.com/forum/showthread.php?t=595515

casey sohc

looks like a good idea.i wonder how waterproof it is?????

infidel

Is it any more or less waterproof than a real Poi-loc?
I've never seen the real thing before.

Lil Dog

Casey sohc, Great photos. Really helps explain the function of the CAD..