I know this isn't exactly diesel related but on my 1996 Dodge Ram 1500 the CAD axle tends to hang up once engaged. Then when you you try to disengage the 4WD the lever goes to 2WD just fine and the transfer case releases. But the CAD unit holds the axle for extended period like maybe another mile or so. POP! Violently releases you can feel it in the entire truck. I'm not liking the CAD units at all I rather have a solid axle personally way less to go wrong.

That's kinda what I figured. So that tells me there isn't a vacuum issue, but more than likely an issue withy the CAD itself. Cleaning might work, and be free but if any parts are needed I would delete the vacuum portion at a minimum.

If I recall it takes vacuum to engage the collar. It sounds more like the collar or actuator needs cleaned up to me.

I am the same as you Mike. 2WD until you need 4WD and as soon as you can go back to 2WD.

Out here the roads are spotted black ice might have a 100 yards or 1 mile stretch of ice. Instead of in and out of 4WD I gotten used to just backing down the speed travel the slick areas cautiously and then when in the clear pick up the speed to what I'm comfortable with.

I generally run in 2wd as well, just depends on the conditions. But it's always nice to have!

Does it use vacuum to engage or disengage, or both?

Posi lok is a cheap and nearly bulletproof fix/upgrade, to me it seems like a no brainier to get it fixed and working properly. It's obviously having issues, so it's hard to say it will always engage and you wouldn't want to get stuck because of it.

Thanks to ISX. Black vacuum line is to engage and the red to disengage.

Posi-lock is way over the top. Once again this is a low budget truck that has zero value where something like my Cummins still holding excellent value I can and would do something like that if I had a CAD axle. But this 96 Dodge the blue book... Well look for yourself it's not worth the effort.

I agree with you, Michael. The vacuum system has worked for 17 years, so why not fix it for another 10+ years? That in all reality would outlast the truck.

i remember with the older Jeep TJ's and YJ's that had a similar setup we used to take it out and slip a long shaft in it's place. or there is a cable actuator that way it's never an issue again. food for thought.

i remember with the older Jeep TJ's and YJ's that had a similar setup we used to take it out and slip a long shaft in it's place. or there is a cable actuator that way it's never an issue again. food for thought.

Both are options I have also brought up. The $159 for a posi-lok is apparently too much based on the vehicles value. To me it far more than value, its reliability and operation. CADs are known to be junk and unreliable, I am honestly shocked this is the first issue for this truck.

Remember the "old saying"………………….."4WD only gets you stuck worse"!!

Yep!I have owned the vehicle with a faulty CAD and it always seems to fail when you need it. So I guess that's why I'm a little bit biased.

CADs are known to be junk and unreliable, I am honestly shocked this is the first issue for this truck.

Strange, my 1996 Jeep works like a charm and my daughter's 1998 Ram works like it is supposed to also.

I had the CAD vacuum actuator go out on my old truck and instead of paying $150+ for a posi-lok kit I put my own together for under $20 at the parts/hardware store. All I had to get was a locking choke cable ($15) and then a compression fitting that fit the cable and a spring (about $1 each) Then I drilled and tapped a hole in the CAD shift housing for the compression fitting and drilled a hole for the cable in the shift fork and and I had 4wd again As for why yours releases the way it does it almost sounds to me like the collar/axle splines may be a little damaged, as long as the vacuum system is working as it should.

Strange, my 1996 Jeep works like a charm and my daughter's 1998 Ram works like it is supposed to also.

Dodge/Ram quit using them for 13 model years, my understanding is that it was a decision based on warranty and reliability issues. They brought them back in MY13 and I think it was a huge mistake, consumers asked for hubs but they went CAD. Time will tell on the new system. Like i I said I am a little biased, I have never owned a rig with a flawless CAD except the 4Runner my wife drives now.

The CAD system is a brutally easy setup. If the posi lock is only $159 then that does seem smarter but the CAD can be fixed and go another 10 years. If you clean it every summer and blow the vacuum lines out then I would think it would be good for a long time. I don't know what makes the valves go out being they are not really exposed to anything, its just a sealed little thing. They are very cheap. If the thing did go out, vacuum line got whacked off going through some snow drifts, that would suck to have to get under there when a posi lock would probably eliminate that. Up to you, if it were me I would fix the CAD and put some fancy braiding on the vacuum lines and make sure they were tucked away, but thats only because it is simple and really a solid setup. Everything has risks and the vacuum crap is probably overly complicated but it does work pretty slick when it does work. Damned if you do damned if you don't. Personal preference either way.

Well technically this is not my primary truck for driving typical it just that fuel prices are wacky again so I'm using the gas powered truck more so why gasoline is cheap. But Since I rarely ever use the 4WD and notice it was violent about releasing I'm not expecting to to major overhaul of the engagement system since it still engages just fine. It just the release is violent and doesn't want to release in a timely fashion so it keeps the axle locked excessive period of time and with a loud THUNK! you hear the axle release and all is good. I guess I'll have to get off my rear end tomorrow and get the shop heated up and get it looked at so I can finish this thread out. It seem the vacuum lines are hooked up but I'll check to see if the vacuum is actually there or not.

Make sure you check the hoses at the t-case real close. It kind of sounds like a cracked line for the release.

I rarely use 4WD. When I do, I have to figure out which way to turn to relieve the pressure so it'll unlock again. Probably means I didn't really need 4WD as there wasn't enough slip to the ground but I'm trying to save the lawn, pulling a trailer out or such. I try to use 4WD occasionally, just to exercise the mechanism.

I rarely use 4WD. When I do, I have to figure out which way to turn to relieve the pressure so it'll unlock again. Probably means I didn't really need 4WD as there wasn't enough slip to the ground but I'm trying to save the lawn, pulling a trailer out or such. I try to use 4WD occasionally, just to exercise the mechanism.

I didn't think 2001.5's had CAD? Or are you talking release the transfer case? I will also use 4wd for braking, it's one more thing keeping the tires from locking.

My early 02 has it. Looks almost identical to Mikes picture. I dont have to do anything special after taking it out of 4wd, just shift it back into 2w and drive off. I dont use 4wd very often or very long.

I did a little more reading on it, seems it was a mid MY02 change.

I will also use 4wd for braking, it's one more thing keeping the tires from locking.

...what? Elaborate.

...what? Elaborate.

If the transfer case is locked into 4wd then if one driveshaft is spinning then the other one has to be as well. This means that if both front or rear tires were to hit a slick spot and try to lock up then at least one tire on the opposite axle would have to stop as well, if the opposite axle has traction at least one tire won't lock up. Every 4wd rig I have owned stops/stopped better on snow/ice when in 4wd than 2wd. Even my wifes 4Runner has noticeably better braking in AWD than 2wd.

I didn't think 2001.5's had CAD? Or are you talking release the transfer case? I will also use 4wd for braking, it's one more thing keeping the tires from locking.

If the transfer case is locked into 4wd then if one driveshaft is spinning then the other one has to be as well. This means that if both front or rear tires were to hit a slick spot and try to lock up then at least one tire on the opposite axle would have to stop as well, if the opposite axle has traction at least one tire won't lock up. Every 4wd rig I have owned stops/stopped better on snow/ice when in 4wd than 2wd. Even my wifes 4Runner has noticeably better braking in AWD than 2wd.

Very true. Like coming down a slick dirt road 4WD will help in keeping the the axle from sliding. But once it does start to slide its really tough to recover the traction again if you have long stretches of ice/snow covered roads. I've also notice the same thing on ATV's the tend to follow this rule as well. Another thing make sure your exhaust brake is off that a great way to get a 4 wheel slide started just hit the exhaust brake and she'll start to glide on you. As for the CAD unit. Wasn't much wrong with it. It had been stuck by road debris and bent the vacuum diaphragm can so it would pull fine to engage 4WD but had troubles returning to 2WD. Vacuum was at both ports as selected. But since the can was bent it was binding the rod slightly. So I removed the CAD unit and took it over to the work bench to pop the E clips out to remove the vacuum diaphragm unit for straightening. First clip. No problem. Second clip! Ting. Tap. Tang. $__T! Damn thing went flying across the shop never found it. 3rd one was easy after the one flew. So using my table vise I clamped to the base hex and was lightly prying up with a screw driver straightening the shaft side of the vacuum diaphragm. Got it just about perfect again. So off to Riggins, ID to get a 22 cent E clip. (Grrrr!) Ok. But get back home and assembly it back together and it works good. CAD unit locks and unlocks just fine now but the transfer case is a bit slow to release. So if I pause along the road and shift either to 4WD to 2WD it will engage/disengage just fine but rolling it will unlock the CAD but hold the front shaft turning till I stop.