1999 dodge ram 1500 will not stay engaged in 4 wheel drive
#21
12-26-2019, 09:36 AM
They stopped that two-piece axle cr@p on the Jeep XJs, ZJs, and TJs; but I don't know why at the same time they continued it on the Gen 2 Ram 4x4s.
#22
12-26-2019, 10:35 AM
They stopped that two-piece axle cr@p on the Jeep XJs, ZJs, and TJs; but I don't know why at the same time they continued it on the Gen 2 Ram 4x4s. Minimal (if any) improvement in MPG with the two-piece axle design. If there was an improvement in MPG, don't you think Jeep would have kept the CAD in those models?
At best, it works "ok" when everything is working right, but there are too many parts to the CAD system - in that if any part stops working, the whole thing doesn't work. Even when mine was working right, there would still be a slight delay from when I pulled the lever to when the 4x4 light came on (especially if I hadn't used 4WD in a while). And sometimes that delay time (even if just a few seconds) was critical.
I'm telling you - get the perm-lok (see post #16 above). No more getting stuck because you can't get the front axle to engage. No more laying in the snow trying to find out where your vacuum leak is. No more tracing vacuum lines for cracks/leaks. No more heating-up your frozen lines and then trying to blow them clear to get your 4WD to work. No cables to pull (like the similar but more expensive and complicated posi-lok). And probably most important, no more wondering if it'll engage when you really need it.
https://www.summitracing.com/parts/pos-400/overview/ (the more complicated and expensive Posi-lok - if you really feel the need to have your front axle shaft separated at times)
https://www.summitracing.com/parts/pos-1100/overview/ (the one you want - the cheaper and simpler Perm-lok)
http://www.alloyusa.com/permanent-di...am-pickup.html (an even cheaper place to get the Perm-lok)
And I'm running a true-trac in the front axle - even with the perm-lok you don't even know it (true-trac) is there in 2WD.
At best, it works "ok" when everything is working right, but there are too many parts to the CAD system - in that if any part stops working, the whole thing doesn't work. Even when mine was working right, there would still be a slight delay from when I pulled the lever to when the 4x4 light came on (especially if I hadn't used 4WD in a while). And sometimes that delay time (even if just a few seconds) was critical.
I'm telling you - get the perm-lok (see post #16 above). No more getting stuck because you can't get the front axle to engage. No more laying in the snow trying to find out where your vacuum leak is. No more tracing vacuum lines for cracks/leaks. No more heating-up your frozen lines and then trying to blow them clear to get your 4WD to work. No cables to pull (like the similar but more expensive and complicated posi-lok). And probably most important, no more wondering if it'll engage when you really need it.
https://www.summitracing.com/parts/pos-400/overview/ (the more complicated and expensive Posi-lok - if you really feel the need to have your front axle shaft separated at times)
https://www.summitracing.com/parts/pos-1100/overview/ (the one you want - the cheaper and simpler Perm-lok)
http://www.alloyusa.com/permanent-di...am-pickup.html (an even cheaper place to get the Perm-lok)
And I'm running a true-trac in the front axle - even with the perm-lok you don't even know it (true-trac) is there in 2WD.
#23
12-26-2019, 01:30 PM
Are you certain that you are losing drive from the front axle? There could be a problem with a 4wd light circuit.
Did you check vacuum on both ports at the actuator? Remove the actuator and see how it behaves when you switch between 2wd and 4wd. If the actuator moves, try to move it opposite direction of vacuum by hand, both 2 and 4wd. Can't say how much force it takes to move functioning actuator. Because splines at the axle shaft are straight cut, it does not take too much force to hold 4wd engaged. While you have actuator out, check the splines at the axle shaft and collar. You can't visually see the collar splines, but if you align the shaft splines, collar should move rather freely.
Since you have a diesel, there shouldn't be any check valve issues. Mine does not hold vacuum either, but vents and 4wd work just fine. I had problem with 4wd not engaging (14 years ago!), I zip tied all the swallen rubber elbows and checked 4wd vacuum switch at the t-case (check that you have line connector all the way down on the switch), and finaly pulled the actuator from the CAD. Turns out the actuator shaft had corroded to the housing. Little WD40 action and haven't had issues with vacuum side of the 4wd system. It's not that bad of a system, works fine in sub zero temps, too.
If you go with posi-lok, just locate the vacuum line at the firewall to the t-case and plug it. If you want your 4wd light to operate correctly, you'll need to change the vacuum switch at the t-case to a light switch.
Did you check vacuum on both ports at the actuator? Remove the actuator and see how it behaves when you switch between 2wd and 4wd. If the actuator moves, try to move it opposite direction of vacuum by hand, both 2 and 4wd. Can't say how much force it takes to move functioning actuator. Because splines at the axle shaft are straight cut, it does not take too much force to hold 4wd engaged. While you have actuator out, check the splines at the axle shaft and collar. You can't visually see the collar splines, but if you align the shaft splines, collar should move rather freely.
Since you have a diesel, there shouldn't be any check valve issues. Mine does not hold vacuum either, but vents and 4wd work just fine. I had problem with 4wd not engaging (14 years ago!), I zip tied all the swallen rubber elbows and checked 4wd vacuum switch at the t-case (check that you have line connector all the way down on the switch), and finaly pulled the actuator from the CAD. Turns out the actuator shaft had corroded to the housing. Little WD40 action and haven't had issues with vacuum side of the 4wd system. It's not that bad of a system, works fine in sub zero temps, too.
If you go with posi-lok, just locate the vacuum line at the firewall to the t-case and plug it. If you want your 4wd light to operate correctly, you'll need to change the vacuum switch at the t-case to a light switch.
Last edited by HeikIlm; 12-26-2019 at 01:50 PM.
#24
12-26-2019, 03:06 PM
Are you certain that you are losing drive from the front axle? There could be a problem with a 4wd light circuit.
Did you check vacuum on both ports at the actuator? Remove the actuator and see how it behaves when you switch between 2wd and 4wd. If the actuator moves, try to move it opposite direction of vacuum by hand, both 2 and 4wd. Can't say how much force it takes to move functioning actuator. Because splines at the axle shaft are straight cut, it does not take too much force to hold 4wd engaged. While you have actuator out, check the splines at the axle shaft and collar. You can't visually see the collar splines, but if you align the shaft splines, collar should move rather freely.
Since you have a diesel, there shouldn't be any check valve issues. Mine does not hold vacuum either, but vents and 4wd work just fine. I had problem with 4wd not engaging (14 years ago!), I zip tied all the swallen rubber elbows and checked 4wd vacuum switch at the t-case (check that you have line connector all the way down on the switch), and finaly pulled the actuator from the CAD. Turns out the actuator shaft had corroded to the housing. Little WD40 action and haven't had issues with vacuum side of the 4wd system. It's not that bad of a system, works fine in sub zero temps, too.
If you go with posi-lok, just locate the vacuum line at the firewall to the t-case and plug it. If you want your 4wd light to operate correctly, you'll need to change the vacuum switch at the t-case to a light switch.
Did you check vacuum on both ports at the actuator? Remove the actuator and see how it behaves when you switch between 2wd and 4wd. If the actuator moves, try to move it opposite direction of vacuum by hand, both 2 and 4wd. Can't say how much force it takes to move functioning actuator. Because splines at the axle shaft are straight cut, it does not take too much force to hold 4wd engaged. While you have actuator out, check the splines at the axle shaft and collar. You can't visually see the collar splines, but if you align the shaft splines, collar should move rather freely.
Since you have a diesel, there shouldn't be any check valve issues. Mine does not hold vacuum either, but vents and 4wd work just fine. I had problem with 4wd not engaging (14 years ago!), I zip tied all the swallen rubber elbows and checked 4wd vacuum switch at the t-case (check that you have line connector all the way down on the switch), and finaly pulled the actuator from the CAD. Turns out the actuator shaft had corroded to the housing. Little WD40 action and haven't had issues with vacuum side of the 4wd system. It's not that bad of a system, works fine in sub zero temps, too.
If you go with posi-lok, just locate the vacuum line at the firewall to the t-case and plug it. If you want your 4wd light to operate correctly, you'll need to change the vacuum switch at the t-case to a light switch.
#25
12-26-2019, 04:43 PM
#26
12-26-2019, 09:52 PM
Are you certain that you are losing drive from the front axle? There could be a problem with a 4wd light circuit.
Did you check vacuum on both ports at the actuator? Remove the actuator and see how it behaves when you switch between 2wd and 4wd. If the actuator moves, try to move it opposite direction of vacuum by hand, both 2 and 4wd. Can't say how much force it takes to move functioning actuator. Because splines at the axle shaft are straight cut, it does not take too much force to hold 4wd engaged. While you have actuator out, check the splines at the axle shaft and collar. You can't visually see the collar splines, but if you align the shaft splines, collar should move rather freely.
Since you have a diesel, there shouldn't be any check valve issues. Mine does not hold vacuum either, but vents and 4wd work just fine. I had problem with 4wd not engaging (14 years ago!), I zip tied all the swallen rubber elbows and checked 4wd vacuum switch at the t-case (check that you have line connector all the way down on the switch), and finaly pulled the actuator from the CAD. Turns out the actuator shaft had corroded to the housing. Little WD40 action and haven't had issues with vacuum side of the 4wd system. It's not that bad of a system, works fine in sub zero temps, too.
If you go with posi-lok, just locate the vacuum line at the firewall to the t-case and plug it. If you want your 4wd light to operate correctly, you'll need to change the vacuum switch at the t-case to a light switch.
Did you check vacuum on both ports at the actuator? Remove the actuator and see how it behaves when you switch between 2wd and 4wd. If the actuator moves, try to move it opposite direction of vacuum by hand, both 2 and 4wd. Can't say how much force it takes to move functioning actuator. Because splines at the axle shaft are straight cut, it does not take too much force to hold 4wd engaged. While you have actuator out, check the splines at the axle shaft and collar. You can't visually see the collar splines, but if you align the shaft splines, collar should move rather freely.
Since you have a diesel, there shouldn't be any check valve issues. Mine does not hold vacuum either, but vents and 4wd work just fine. I had problem with 4wd not engaging (14 years ago!), I zip tied all the swallen rubber elbows and checked 4wd vacuum switch at the t-case (check that you have line connector all the way down on the switch), and finaly pulled the actuator from the CAD. Turns out the actuator shaft had corroded to the housing. Little WD40 action and haven't had issues with vacuum side of the 4wd system. It's not that bad of a system, works fine in sub zero temps, too.
If you go with posi-lok, just locate the vacuum line at the firewall to the t-case and plug it. If you want your 4wd light to operate correctly, you'll need to change the vacuum switch at the t-case to a light switch.
finished replacing the cross member to front axle lines so now I have all new vacuum lines and replaced actuator . The actuator seemed to be the problem as I drove it around in 4x4 for sometime without a problem. Does look like splines could be a little worn so I will know where to start if I have another problem.
#27
12-28-2019, 07:37 PM
The jeeps used different transfer cases(ones with viscous couplings) and they weigh about half of what a ram does. Not to mention smaller motors. I don't think MPG would change all that much in the jeeps but a ram 3500 with the V10 4X4 you would definitely see a difference. Guess it depends on how you use it also, My 4WD only gets used in snow or mud witch is about .02% of the time i drive it.
Last edited by 00t444e; 12-28-2019 at 07:39 PM.
#28
12-30-2019, 05:27 PM
not sure where both check valves are located. I know I have one on the main vacuum line siting right above the pump on the firewall before it splits to all the vacuum lines. Not sure how to tell if it’s bad but my truck won’t hold vacuum after I shut her down.(I don’t have any vent problems) I should go buy a vacuum pump gauge to test if the actuator is leaking but I am just going to replace it and the metal lines today. Just because I know the rubber boots are worn and don’t want them to be a problem down the road. So about the posi lock ... is it bad to have your front axle always locked together? What do you do with the vacuum lines? I do a lot of highway driving. Pros and cons ? I would rather not spend the money on a vacuum actuator if I where to end up switching it anyway.
http://4x4posi-lok.com/app_dodge.html
Is it bad to have the two-piece front axle shafts always locked together? No. It is perfectly fine. My TJ, and the ZJ we built had factory one-piece front axles on the long side (same as having the two-piece axle on the 1500 always connected/locked together) and there are no issues. We have a Truetrac in the front of the ZJ and my 1500's front Dana 44, and I have an Aussie locker in the front axle of my TJ. No issues.
What do you do with the vacuum lines? Throw them out. All of them. Cap off the vacuum source, and replace the vacuum switch thingy on the transfer case with a Jeep TJ transfer case switch and run the wires from the switch that was on the actuator back to the transfer case switch you replaced (you'll just need two wires about 5' long each).Highway driving pros and cons? There are no cons. You won't notice it (shafts connected) on the highway just as I don't notice it on my TJ when on the highway (nor do I notice it on my truck). These Dodge trucks get pretty poor gas mileage whether or not you've got the front axle shafts locked all the time or not. Pros: you won't have to worry about a CAD system vacuum leak that can cause other issues (cruise control not working, HVAC settings being weird, etc.). You'll know that if you need to put it into 4WD it will go into 4WD immediately when you pull the lever.
And as a reminder to folks, "locking" the two-piece front axle shafts together on the one-side of the axle (long side) DOES NOT give you a "locker" in the front axle. This isn't the same as an Ox Locker. All you're doing is making the front two-piece axle into essentially a one-piece axle on the long side by "locking" them together. If you have an open differential in the front axle (the factory differential), you still have an open (unlocked) front axle after the Perm-lok. You need to change out the differential to either a limited slip (like a Truetrac) or a full locker (Detroit locker, etc.).
Last edited by armynurse; 12-31-2019 at 12:18 AM.