NHDiesel

Well since I had yard work to do (pulling many stumps) I needed 4x4 in my truck, so I came up with a temporary solution that should work for any Ram that uses the CAD. I removed the CAD, then removed the "E" clip that locates the shift fork on the shaft. I slid the shift fork over (without the shaft moving...mine was seized anyway) and put the clip back in. That locks the shift fork over in the engaged position. When you reinstall the CAD, move the collar over by hand, then install the CAD. This will keep the axle locked in at all times.

I know this sounds like a bad solution, but its no different than running all winter with the hubs locked in on an older truck, or a newer Ram without a CAD. I call this a temp. solution, but I don't see why it wouldn't work for a somewhat permament repair. I have had mine locked in for a few weeks now, and haven't noticed any difference in driving it or any decrease in fuel mileage. On the other hand, I can easily engage 4x4 on the fly without the usual slight grind as it engages.

This would be easy to do in about 10 minutes with a 7/16" socket and a screwdriver if your CAD calves and you really need 4x4. No cutting, grinding, or other mods necessary.

Jim

infidel

This seems like it would wear your tires out faster if driving on dry pavement.
Might end up costing you more in the long run than repairing it correctly.

vssman

I thought they got rid of the CAD say around 2002. Sounds like it would work as long as the locking collar stays on the "locked" side. If the Posi-lok route is too costly, you can make your own with a cable and lever...

NHDiesel

The collar has to stay locked...the shift fork is holding it locked in. Just as if vacuum was holding it in place, except the "E" clip is whats holding it in place now.

The tires won't wear any more quickly unless you have a locking differential up front. As long as the transfer case shift lever is in 4x2, there is no strain on the front axle, and the differential keeps the tires from wearing. By locking it in, you are just doing the same exact thing as the newer trucks that don't have the CAD.

Jim

ridofpwrstroke

NHD is correct, it will not wear your tires any more at all. The shafts in the axle tubes are always spinning. My 02.5 doesnt have the cad and I wish I did. The alternate to the vacuum is the posi lock. My wifes 98 has the CAD and it works great. Havent had a problem where I needed 4x4 and it wouldnt switch. On my 92 dakota, I did have to replace a vacuum line because it wouldnt switch.

NHDiesel

I would definately put in a Posilock over keeping it locked...thats why i called this a temporary fix, but there really isn't any reason the axle couldn't be left locked in. I plan to get a Posilock when i have the funds, but for now this is working...and winter is coming anyway, so I'll be fine until spring. If I had a Posilock, it would be staying locked from next month until April anyway just so the shifts in and out of 4x4 are smoother.

There is one very minor drawback, and that is that the u-joints on the front driveshaft will wear slightly quicker because its always spinning. But again...no different than the 3rd gen trucks.

By the way, whats the easiest way to convert to manual hubs? I don't think there is a kit for the Dodges, is there? I think swapping in a Ford axle (and leaf springs!) would solve many problems at once, including getting rid of the cheesy coil spring/track bar issues, get rid of the ball joints and replace them with kingpins, and provide manual hubs.

Jim

Rockyhud

Unless I'm mistaken (it could happen ) all front axle components are rotating regardless of whether or not you're running 4x2 or 4x4 mode, including the front driveshaft. Unless the front driveshaft and axle parts are turning you wouldn't be able to engage 4x4 on the fly as there would be a serious mismatch in gear and axle speeds (rear parts would be turning, front parts would be setting still). What happens when you engage 4x4 mode is the shift fork on the front axle slides the locking collar over to the outer axle shaft on the passenger side (which happens because all parts are rotating the same speed) which then allows torque to be applied to the front right wheel. Now that both wheels in front have power applied the front open diff will be what "decides" which side gets power and which doesn't, via the open diff's spider gears, thus enabling the front axle to provide pulling power. With the CAD in 4x2 mode power is still sent to the front axle, but because the open diff will send power to the side that has the least traction it would be sent to the side with the CAD (due to no traction/resistance to the axle turning compared to the other side) and no power sent to the other side, thereby not providing any power to the drive's side wheel. Hope that makes sense.

Steve

NHDiesel

Actually that is off a bit. In 4x2 mode, no power is sent to the axle, because the transfer case is unlocked. Thats why in 4x2 you can crawl under the truck and spin the driveshaft by hand. Yes, many parts are spinning, but not everything that spins in 4x4 mode.

4x2: Power is sent through the transmission, to the transfer case, and out the rear output to the rear axle. Nothing is transferred to the front driveshaft. The passenger side tire is turning forward, as is the outer axle shaft (as far as the CAD). The driver's side axle is also spinning forward, as far as the differential. At the differential, because of the design of the differential, the carrier and ring gear don't turn. The passenger side inner axleshaft turns in the opposite direction (backwards). The driveshaft doesn't turn. If you jack up both front tires and spin the driver's side tire, you'll see that the driveshaft doesn't turn. Try doing it with the CAD removed, and if you have someone on each side turning tires forward, you'll see the axle shafts spinning in opposite directions. In the real world, when you are driving at high speed, the friction inside the differential does make the driveshaft spin a bit, but there is no mechanical connection to anything. If you were to reach out and grab onto it, it would stop turning.

When you pull the lever to engage 4x4, the first thing that happens is that the transfer case engages. You'll hear a bit of a grinding/clunk as it engages, because it has to bring the front driveshaft up to speed. When the lever reaches the 4x4 position (driveshaft already spinning), the vacuum switch is engaged inside the transfer case, supplying power to the axle disconnect. Because the first thing to engage is the transfer case and driveshaft, the axles are now spinning in the same direction, allowing the collar to slide over. The vacuum takes a few seconds to build up enough pressure to slide the collar, which is enough time for the transfer case to fully engage.

Jim

ridofpwrstroke

Roger that Jim, where the CAD is, the drivers side axle is spinning forward and in turn make the spider gears spin, the shaft coming out of the passenger side of the carrier is spinning backwords to where the cad is. Everything else you said is correct. That is why detroit lockers and lock rites will not really work. The drivers side does all the work and the driveshaft will still spin with the CADS. It will not allow the gears to spin backwords.

NHDiesel

Yup, we're saying the same thing, just different. :-) What I meant is that the axleshaft between the differential and CAD is spinning backwards (passenger inner-inner shaft, as opposed to the passenger inner shaft thats between the CAD and passenger side U-joint? hard to describe without pics...lol).

Jim

'pants

I'm eleven years late to this party, but since my CAD has left me with scary sudden disengagement (always while backing up my steep-as-hell driveway), I'm REALLY interested to know if there's truly a negligible downside to doing this simple mod. Seems like Mopar would have realized they could have cut their production-costs a lot by eliminating the CAD if there were not some significant advantage to keeping it. I want to believe otherwise.

In practice, isn't it much "grindier" trying to get from 2H to 4L? I don't need to do anything on the fly in my typical use (didn't think that was recommended or possible anyway for a 2nd generation, is it?)

--Dave

vssman

Wow, talk about a blast from the past. I didn't feel there was any downside to the Posi-Lok set up. I guess the push to move to a CAD system was to adapt the 4X4 system to be more "friendly" to the average consumer as well as eliminate cost vs having locking hubs. I no longer have my Cummins (unfortunately) and my new trucks system makes me wish for the CAD unit. It's now electronic and position feeds back into the ecu for stability control, etc... I hope it never breaks as the motor control unit is over a grand for the part. But back to the Cummins - you could lock the front on the fly even with the Posi-Lok provided the transfer case was engaged first to spin the front driveshaft and mechanicals to the same speed as the wheel side of the front driveline.

'pants

Thanks vssman - I feel like I'm stuck in 2005, on my end of things.

I may be missing part of your point, but my real question assumes no Posi-Lok or CAD, but rather with front shafts joined semi-permanently by $0 fork-reversal in the stock CAD. Under those conditions, would shifting from 2H to 4L be a tooth-grinding experience, whether on the fly or not? (I don't really need to be moving, but could be...thought the visor instructions were to go into N before making the shift, though).

--Dave

vssman

If you lock the CAD with whatever means you choose, you'll be able to switch from 2wd to 4wd on the fly without any grinding. Tire wear and a bit of fuel mileage will suffer leaving the front end locked, that's all.

ihc4bt

I installed the Posi- Lock cable onto a 97. It works flawlessly. When I had the vacuum CAD go out in my 94 I tried the ALLOY cable operated CAD that 4 wheel parts sells. It is garbage. I tried it because it was in stock and less money than the Posi-Lock. I had problems adjusting it. When I had it adjusted where it would engage properly, you could here a clicking/grinding noise from the front end after hitting a bump. When I changed the adjustment It would not engage or disengage when adjusted the other way. I played with this thing for about 2 weeks. I was out robbing another part off my 1500 parts donor and I noticed the CAD was the same. I took it off and put it on my 94 2500 and it started working again like factory. I like the cable because you can use 2wd low when backing heavy trailers, just like a truck with manual hubs. In short pay the extra for Posi-Lock and skip the Alloy brand