New member-odd problem

[WAPresley]

I'm having a problem that after being in shops literally a total of two months is still undiagnosed. The last place I took it was convinced the problem was in the transfer case but they don't work on that there. I figure if anyone could give me a better idea than just "pretty sure its in the transfer case" the folks on here could.
The issue is that anytime I hit a significant bump, and often even a slight one, with the front passenger side tire the truck behaves as if its dropping into 4-low just in that tire. Once I show down to about 20mph it goes back to normal. It Boggs the truck down so much I have no choice but to pull over anyway but it tends to irritate the other traffic. Wheel bearing, Axel, brakes, steering dampener and tires are new. All the other external front end parts have been judged in good shape by the shops. I'm really hoping out could be something simpler they may have missed, none of them were 4X4 specialists and I dint have one close by. Truck is a 96 1500, 5.9.
Posting this on a phone with fat fingers, sorry for any typos. Thanks for taking the time to consider the problem.

 

[zack]

Not sure buddy but welcome to rf ..it almost sounds like death wobble but I'm not sure it happens to the 1500s

 

[WAPresley]

Thanks for the welcome. Its just that one tire though. Truck doesn't shake at all, just Boggs down like that one tire is in low. I thought the fender had fallen and was grinding against the tire tread at first but the obvious stuff, obvious to the ones who've looked at least, has been ruled out. Pretty much makes the truck undependable. It runs great but pulling over for every bump is a pain. Sometimes even the transition going onto a concrete bridge from pavement is enough to do it.

 

[Joshwaa]

I do not know a lot about that year? Are there auto locking hubs on it? Air/Vac actuators?

 

[GhostRam94]

hmm idk, does the shifter ever move, i have never heard of this problem

 

[WAPresley]

It has the four wheel drive shifter in the floor (auto transmission) and the on the fly four wheel drive. I've been told its vacuum controlled but I'm a complete novice with 4x4's. When the problem kicks it there's no real vibrating, though you can feel it. It feels and sounds like I'm trying to do forty in first hear which is why I assumed its drooping into low. Most of the mechanics think so to even though they couldn't identify the cause. I've only had the truck about six months but thee are no other mechanical problems that I can tell. So far just bearings, tires and IAC module. They replaced the Axel on that side because the first set of bearings they put on busted and damaged it. They've replaced it truce moor, just desperate for a cause I think.

 

[WAPresley]

Haven't ran across anyone else who've heard of it either. They've had them engage the four wheel drive on their on but never one wheel.

 

[GhostRam94]

hmmm thats weird, never heard of having both on the fly and on the floor, that might be why

 

[Joshwaa]

If you are vac actuated that could be your problem right there...

 

[WAPresley]

The shifter to go from 2h-4h-neutral-4L is in the floor. Which I thought made it purely mechanical but the mechanic said vacuum. I'm starting to think my problem is the caliber of mechanics I'm coming across. But like I said I'm a novice, I still make noises to describe the problem, so I gotta trust them.
If its a problem with the vacuum system (which they claim to have ruled out) the tricky part is why hitting a bump sets it off.

 

[WAPresley]

And...I just realized I pasted this in the diesel forum. Sorry about that, screens a little cramped on this phone. Maybe a moderator could move it to the second gen forum for me?

 

[WAPresley]

I originally posted this in the diesel by accident, sorry for any confusion.

I'm having a problem that after being in shops literally a total of two months is still undiagnosed. The last place I took it was convinced the problem was in the transfer case but they don't work on that there. I figure if anyone could give me a better idea than just "pretty sure its in the transfer case" the folks on here could. The issue is that anytime I hit a significant bump, and often even a slight one, with the front passenger side tire the truck behaves as if its dropping into 4-low just in that tire. Once I show down to about 20mph it goes back to normal. It Boggs the truck down so much I have no choice but to pull over anyway but it tends to irritate the other traffic. No heavy vibrations, just like you're trying to drive too fast in low gear. Wheel bearing, Axel, brakes, steering dampener and tires are new. All the other external front end parts have been judged in good shape by the shops. I'm really hoping out could be something simpler they may have missed, none of them were 4X4 specialists and I dint have one close by. Truck is a 96 1500, 5.9. Posting this on a phone with fat fingers, sorry for any typos. Thanks for taking the time to consider the problem.

 

[Mopar1973Man]

Some how I don't see a axle doing such a thing unless it was a faulty brake calliper which you said was dealt with.

Because there no gear reduction in the front axle capable of pulling the truck down other than brakes. If only one axle was dragging as you describe then the truck would pull hard to one side too.

You might have to do so more investigating...

But here is a vacuum map...
Mopar1973Man's Dodge Cummins Articles - Central Axle Disconnect (CAD) System Troubleshooting

 

[WAPresley]

Thanks! Never considered it in the problem but the truck doesn't pull to the side at all. I'll start teaching the vacuum lines as soon as the weather breaks here. I appreciate the help!

 

[Bigtman07]

Well welcome sir. Sounds to me like it could be the CAD. It's the actuator that actually engages the 4x4. Its on that side of the axle. If it is broken loose or otherwise not connected correctly the collar in there could be sliding over the axel engaging the 4x4 but the transfer case is not engaged. So it is turning the gears inside the transfer case and the axle.

Here is what I would do. I would crawl under there and check the vacuum lines for breaks and cracks. The CAD is on the passenger side on the axle. Can't miss it. I think 4 bolts hold it on. Take those 4 out. Get a catch pan and pull it out. check the device. Make sure it has resistance. If not I think you found your issue. Check the collar too while you are int here. Make sure it isn't chewed up. Hope that helps. If ya need pics of what you're looking for let us know. I'm sure one of us can hook you up.

 

[WAPresley]

Will do, thanks! I think I've seen what you're taking about, I just didn't know what I was seeing. I have the manual so now that I have a name for what to look for I should be able to follow your suggestion. If not I'll be back to beg. This thing has frustrated me will past being shy about asking for help. There's several things I'll need to do to this truck once I can actually drive it without worrying. Looking forward to being on here.

 

[Bigtman07]

No problem glad to help. You get the service manual from the DIY section? Big help.

That is at least where I would start. Gotta have a starting point. Let us know what you find. We will get this figured out!

 

[WAPresley]

I have the Haynes manual but I'll check the DIY section. And yea, having a logical place to start looking is a stress reliever all by itself. After the fifth or so mechanic told me they could so a bounce test cause maybe it's the shocks I was borderline violent. I'll update as soon as weather lets me get under there.

 

[WAPresley]

Well, got the old part off. The resistance seems ok but I'm changing the part out since I've already bought it ($96 @ Napa) and with the miles on this truck I guess it won't hurt to get the replacement out of the way. I don't have complete faith in my judge of what's good enough resistance anyway.
The collar seemed ok and the gear didn't looked worn. The catch pan turned out to be unnecessary though, not a drop of fluid came out. I could tell it was leaking before I dropped the part. Should there have been a good amount of fluid draining when I took the part off? I'm taking some pics as I go. Not sure if there is a DIY on this already but they may be useful to someone.
Crossing my fingers, really need this thing running since my teenage daughter is waiting with bated breath to take over the car...

 

[Bigtman07]

Lol well some fluid should come out because the differwntial fluid is what lubricates that actuator. And there isnt a diy yet so if you want a write up go for it. Let us know if it helps.

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