CAD / Pressure idea for slow engage/disengagement
Record Breaker
Joined: Aug 2007
Posts: 2,283
Likes: 2
From: live oak, ca
would the pressure system work? yes. would it be practical in any way? not a chance.
you first would have to have a means of providing pressure all the time, then a complex valving system to provide pressure to one side of the diafram and open the other side then visa versa to switch it in or out, if there isnt pressure to one side all the time it can move and deside to shift when ever it wanted, you would need some sort of regulator, my guess is anything over about 20psi would pop the diafram, then you still have all of the same comprmised, and reliabilty issues as the original system, lines to get tore off or broke, diafram and valving issues and so on,
i would go with the posi lok or repair the original system, adding a pressure system would be that more of a headake not to mention time consuming, way more expensive than a posi lok, and more than likely, even more problems than before.
i dont mean to be riping your idea, i just dont want to see you waist your time and money if you dont have too
you first would have to have a means of providing pressure all the time, then a complex valving system to provide pressure to one side of the diafram and open the other side then visa versa to switch it in or out, if there isnt pressure to one side all the time it can move and deside to shift when ever it wanted, you would need some sort of regulator, my guess is anything over about 20psi would pop the diafram, then you still have all of the same comprmised, and reliabilty issues as the original system, lines to get tore off or broke, diafram and valving issues and so on,
i would go with the posi lok or repair the original system, adding a pressure system would be that more of a headake not to mention time consuming, way more expensive than a posi lok, and more than likely, even more problems than before.
i dont mean to be riping your idea, i just dont want to see you waist your time and money if you dont have too
Thread Starter
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Professional
Joined: May 2008
Posts: 243
Likes: 1
From: Ontario, Canada
For one, the design is vacuum actuation for engaging anf disengaging, there is no pressurized supply. The vacuum switch on top of the transfer case determines which side of the supply line has suction or not. It does not switch between suction and pressure. You would have to find a way to provide pressurized air, not an easy task on thse trucks.
But that all pales next to my real meaning. Read DVaughn's comments, because he's right on the money. As I said, the system sucks (no pun intended), not for any one reason, but for a multitude of reasons. It is poorly designed and easily compromised. Think about it, The CAD does not switch you from 2X4 to 4X4, it switches you from 3X4 to 4X4. When you shift into 4HI or 4LO you are connecting the transfer case output directly to the left front wheel. The CAD simply connects the right front wheel to the system, it does not have anything to do with anything else. It doesn't stop front axle parts from moving because those are already connected via the left front axle shaft. The CAD was a brain fart on the part of Chrysler engineers as was the idea of using 25 feet of damage or failure prone vacuum tubing to control it. The cable system is much more practical.
But that all pales next to my real meaning. Read DVaughn's comments, because he's right on the money. As I said, the system sucks (no pun intended), not for any one reason, but for a multitude of reasons. It is poorly designed and easily compromised. Think about it, The CAD does not switch you from 2X4 to 4X4, it switches you from 3X4 to 4X4. When you shift into 4HI or 4LO you are connecting the transfer case output directly to the left front wheel. The CAD simply connects the right front wheel to the system, it does not have anything to do with anything else. It doesn't stop front axle parts from moving because those are already connected via the left front axle shaft. The CAD was a brain fart on the part of Chrysler engineers as was the idea of using 25 feet of damage or failure prone vacuum tubing to control it. The cable system is much more practical.
Exactly what I meant by having on board air, say if you were running a set of air horns or something. I realize that both lines "suck". One to engage, the other to disengage, thus why I suggested pressurizing to engage and disengage.
So when they talk about having 2LO with posi-lok, in reality its 3LO?
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Professional
Joined: May 2008
Posts: 243
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From: Ontario, Canada
Hmm... now I'm confused lol.
I thought the T case engaged the front left wheel, and the cad connects the right front wheel.
If this is not the case, then what prevents the left front axle from connecting when you use this "2LO" ?
I thought the T case engaged the front left wheel, and the cad connects the right front wheel.
If this is not the case, then what prevents the left front axle from connecting when you use this "2LO" ?
Record Breaker
Joined: Aug 2007
Posts: 2,283
Likes: 2
From: live oak, ca
well in a sence the t-case is connected to the left front, but with the cad dissconnected, the diff just spinns freely becuse there is nothing hooked to the right side, and wont transfure power to either wheel
thank you dodge trucker, i was juts about to say that, because when i got stuck(still waiting on pics) and my cad wasnt working, if it had really been 3x4 i wouldve been able to get myself out because the extra pull wouldve helped. really youre only in 2x4
Banned
Joined: Apr 2009
Posts: 2,816
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From: Los Angeles, CA
This is true so long as you have the stock open differential. With a locker of some kind you will definitely have a 4X3. Even with the CAD engaged, if one front tire loses traction you might as well be in 2X4 because the rear wheels will be the only ones getting any power. We call these trucks 4X4s, but the reality is they need some modification to truly be 4-wheel drive in all situations. The stock open front diff is practically useless unless you keep all 4 wheels on dry ground.
Captain
Joined: Oct 2009
Posts: 730
Likes: 10
From: Near Charlotte, NC
This is really interesting stuff here thanks to all for you're thoughts...
But I have a question how many of you actually shift on the fly (over 5 mph) with these trucks?
Anytime I tried I had gear clash.
Just wonderin'
But I have a question how many of you actually shift on the fly (over 5 mph) with these trucks?
Anytime I tried I had gear clash.
Just wonderin'
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Professional
Joined: May 2008
Posts: 243
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From: Ontario, Canada
I usually accelerate a bit, then just as I'm making the transition to decelerate, I gently pull the 4wd shifter, and it clicks right in. The CAD on the other hand... lol... hence this thread.
