CAD options

[brucecooner]

I'm curious what, exactly, the CAD keeps from spinning.

 

I know it disconnects the passenger side front wheel.

Does that mean your diff is still spinning with the left front wheel? 

Or is it just the leftmost spider(?) gear in the diff that spins with the left front wheel?

Or is the diff completely static when the CAD is disengaged?

 

Anyway, curiosity aside I'm not really fond of things actuated by vacuum lines that have to stay soft and pliable and puncture free to work.

 

I know there are aftermarket solutions that replace the vacuum actuation with a cable to the CAD.

The thought of having a more physical connection from my hand to the part I want to move appeals to me.

 

Then, there are those guys who just lock it closed and go about their business.

 

Supposedly the CAD increases mileage, and I do plan to put some highway miles on this guy, so I might prefer to keep the CAD but upgrade the actuation.

 

I've wondered if it's possible to replace the passenger side axle with a solid shaft.  It seems that would be more trustworthy against breakage than a collar connecting two shafts.

 

Also, the dash light.  Does that light only tell you that the CAD is engaged? Or do the lights give you actual feedback on the state of the transfer case?  (I'd assume the shifter would be your best bet on that).

I'm not too worried about the dash light not being accurate, UNLESS it's critical for knowing what state the system is in, so you don't do something dumb like go down the highway in 4H.

 

So I'm curious to know what experiences others have had with various solutions.

 

Do you see a noticeable reduction in vibration or mileage with the CAD engaged all the time?

 

Are those wire actuators a good idea?  Or do they have some peculiar quirk that makes them more annoying than vacuum lines?  Is it possible to have the dash light work with a wire based system?

 

 

 

 

 

 

 

 

[cruiser54]

Ditch it with the write-up on here. It was a dumbass design and can be bypassed in 20 minutes.

No need for a light!! Shifter position tells you all you need to know. 

[ghetdjc320]

X2. Go with the method listed above, simple and effective. 
 

And it’s the spider gears that spin internally. Locking the passenger side will cause your driveshaft to spin all the time but you will likely never notice it or any MPG changes

[Pete M]

Jeep itself dumped the design from the Cherokees in the early 90s.  your Jeep will just be like them.  

 

the only real drawback is that if your front driveshaft has warn joints, you'll now notice it at high speeds.   (which is actually a good thing since you should be replacing them anyways) 

[ghetdjc320]

I do like the CAD housings though. That upper control arm mount cast into the cad housing was awesome. The thin sheet metal bracket they added to the passenger side in later years was junk.

[89 MJ]

 

I’m with everyone else. My CAD is deleted and even with my hearing, my best tank of gas was 20 mpg running 70-75mph. Plus it’s shaped like a brick, you’re not going to get great gas mileage either way

[Eagle_SX4]

This is the write up I did on puting TJ shafts into the CAD housing.

 

 

 

With the later shafts you also get the larger u-joints 

 

[pizzaman09]

I'm stubborn and have put much effort into making my CAD work and it does!  Cleaned everything, put it back together, made sure the truck has no vacuum leaks.  I make sure to shift it into and out of 4WD once most times I drive it to exercise the mechanisms and make sure it doesn't get bound up.  Now the CAD instantly engages.  When I first bought the truck it was very challenging to get it to engage. 

 

I don't disagree with wanting to eliminate the failure point of the 4WD system.  

 

I keep mine because I have dreams of someday incorporating some valves to allow for a 2WD low range as I find it quite useful when hitching up to trailers.

[pizzaman09]

20 hours ago, brucecooner said:

Also, the dash light.  Does that light only tell you that the CAD is engaged? Or do the lights give you actual feedback on the state of the transfer case?  (I'd assume the shifter would be your best bet on that).

I'm not too worried about the dash light not being accurate, UNLESS it's critical for knowing what state the system is in, so you don't do something dumb like go down the highway in 4H.

The light does tell you that the CAD engaged.  The switch for the light is vacuum controlled based on a line coming off of the side of the CAD vacuum diaphragm when it has successfully shifted to 4WD.

[brucecooner]

Well it's nearly unanimous, it can be deleted without negative effects.

 

Which leads to my next question.

 

I was checking out my TC the other day and noticed the red and yellow lines are broken right at the TC.

It looks like the other two have been fixed for a break in the same spot, where the lines turn to head to the front of the truck.

So at minimum that's a vacuum leak right there (I think red goes to the intake?)

 

Is the four line vacuum manifold-plug on the transfer case JUST related to working the CAD?

I assume with CAD deleted I can plug those lines at the TC? Or is there an aftermarket plug to just replace that bit on the TC?

 

And on that topic, does anyone know where on the intake manifold the line-to-TC plugs in?

I'd like to just plug it at the manifold and remove the lines if that's an option with the CAD on all the time.

[cruiser54]

Yep. The transfer case shifting takes place as a result of the lever position.

 

All that other vacuum line bull$#!& is totally unnecessary. Block it off at the source. 

[512tr]

On 2/22/2024 at 6:17 AM, brucecooner said:

Also, the dash light.  Does that light only tell you that the CAD is engaged? Or do the lights give you actual feedback on the state of the transfer case?  (I'd assume the shifter would be your best bet on that).

I'm not too worried about the dash light not being accurate, UNLESS it's critical for knowing what state the system is in, so you don't do something dumb like go down the highway in 4H.

I think you still could do the CAD delete and use the vacuum lines to only operate the 4WD vacuum switch and have the 4WD light working when the TC is in 4WD.

 

 

On 2/23/2024 at 2:44 AM, pizzaman09 said:

I keep mine because I have dreams of someday incorporating some valves to allow for a 2WD low range as I find it quite useful when hitching up to trailers.

 

If you feel the need for it, don’t let it be a dream.😊

 

It’s quick and easy to realize in few minutes, just cut the yellow line and install a small valve.

 

If you want it inside the cab just extend both lines to the cab and connect the valve. You could use a small gas valve or as simple as an aquarium air control valve (as I did).

I did this on my YJ a long time ago, to ease maneuver with a trailer in a very tight space.

 

 

[cruiser54]

I've been 4 wheeling since 1967.

 

We lived with levers that had black knobs on top of them with $#!&ty markings on the knobs. That, along with dash plaques explaining how to pull the levers to get the desired result. Those were hard to read from the driver's seat. 

 

Now, in 1984 Jeep comes up with a lever, with a lighted bezel, bright markings as indicators, an easy to read and understand tutorial on the sunvisor.  So we need some cludgy, prone to failure, half-assed vacuum system to trigger an unreliable light that is redundant? 

 

 

[jpnjake]

I didn't see it mentioned,

 but there's one good reason to keep the disconnect working.....

 

 if you ever have to flat tow your Jeep.

 

 

Early 231's with the Vac disconnect switch on them use a different selector plate.

 

^The early selector plate locks the front and rear driveshafts together (4x4) in Neutral,

but unlocks the axle VAC disconnect to keep from binding while towing.

 

Later selector plates had a dedent added along the top profile to disengage the front output in N,

 making the VAC disconnect unnecessary.

 

 

[jpnjake]

I believe in ditching the VAC disconnect,

 

 but you should either:

change the selector plate,

 swap to a T-case with a true neutral,

 or be careful not to flat tow the Jeep for very far to avoid locking up the old T-cases.

[brucecooner]

7 hours ago, jpnjake said:

I believe in ditching the VAC disconnect,

 

 but you should either:

change the selector plate,

 swap to a T-case with a true neutral,

 or be careful not to flat tow the Jeep for very far to avoid locking up the old T-cases.

 

7 hours ago, jpnjake said:

I didn't see it mentioned,

 but there's one good reason to keep the disconnect working.....

 

 if you ever have to flat tow your Jeep.

 

 

Early 231's with the Vac disconnect switch on them use a different selector plate.

 

^The early selector plate locks the front and rear driveshafts together (4x4) in Neutral,

but unlocks the axle VAC disconnect to keep from binding while towing.

 

Later selector plates had a dedent added along the top profile to disengage the front output in N,

 making the VAC disconnect unnecessary.

 

 

 

This was something I was curious about, the lack of a true neutral in some 231's.

I don't plan to ever tow it, but it may have other plans.

I'm going to call Novak and ask about a stem to stern solution next week, and was going to see if their cases included true neutral.

 

10 hours ago, cruiser54 said:

I've been 4 wheeling since 1967.

 

We lived with levers that had black knobs on top of them with $#!&ty markings on the knobs. That, along with dash plaques explaining how to pull the levers to get the desired result. Those were hard to read from the driver's seat. 

 

Now, in 1984 Jeep comes up with a lever, with a lighted bezel, bright markings as indicators, an easy to read and understand tutorial on the sunvisor.  So we need some cludgy, prone to failure, half-assed vacuum system to trigger an unreliable light that is redundant? 

 

 

I am definitely in the "keep it as simple as possible" category.

 

Something else I've wondered about is deleting the CAD for now, then later on getting a little bit beefier front axle with locker functionality and locking hubs.

 

But I've read that locking hubs come with their own set of problems, and some are actually less durable because the innards are more exposed to the environment.

 

 

 

[cruiser54]

This is getting way too complicated.......and off track. 

If you need it towed, request a flatbed tow truck. That's about all they use anymore anyway. 

If you're gonna put a different axle in front, what difference does it make. 

Are you buying a motorhome? If not, don't worry about flat towing it. 

[Pete M]

high pinion CAD-free Dana 30 with the 297 joints is about the best thing out there.   need anything more and you might as well step up to a dana 60.  

 

though a truss is a great idea if you plan on jumping it. 

[cruiser54]

I don't think Bruce is gonna do any of that!!

[brucecooner]

2 hours ago, Pete M said:

high pinion CAD-free Dana 30 with the 297 joints is about the best thing out there.   need anything more and you might as well step up to a dana 60.  

 

though a truss is a great idea if you plan on jumping it. 

 

I don't PLAN on jumping it,  my plan is to keep all four wheels on the ground.

I wouldn't be opposed to new shafts, but pulling the carrier sounds like a good way to muck something up, for me.

 

 

2 hours ago, cruiser54 said:

I don't think Bruce is gonna do any of that!!

 

cruiser knows me.
 

 

I've pulled and tugged on everything underneath the jeep, and everything seems pretty solid.

But I'm wondering now how long it's been since the front drive shaft has turned.

The Jeep has been pretty well maintained over its life, but everything on it is pretty tired.

 

Like I said, I cannot twist or shake either shaft, but I guess I'll have keep in mind I might need to replace some U-joints after the delete.

 

 

 

[cruiser54]

Not necessarily to any of that stuff.

 

Your past useage, future useage, and the fact you're in

Arizona reduces the need for all this stuff you're dreaming about needing. 

[brucecooner]

I got under the front and cleaned 30 years worth of grime off the cad body last weekend, so that when I go to do the delete the messy part is done.

Mine has that semicircular guard under the vacuum actuator, and its upper surface sure holds onto a lot of greasy dirt.

 

Anyway, I've seen a method for the delete in yt videos where they take a couple of hose clamps, 180 degrees off so they're balanced, and use those to keep the collar engaged. As the clamps and collar would all be spinning on the shaft together, nothing should be rubbing anything at differential speeds.

 

I find this appealing, as I can remove the fork (the most reliable part is no part) and just replace the cad plate, actuator, etc. with a flat cover.  I've heard a few stories of the fork breaking, so removing it may prevent a problem the line.

 

It's probably apples to oranges, but has anybody run with this fork delete method?

[cruiser54]

You're overcomplicating something very simple. 

[Pete M]

you don't even need to use 2 hose clamps.  the weight of the clamp is insignificant and won't cause balance issues to the shaft.   

[cruiser54]

Just do it Pete's way and be done with it.