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Hello, I have a 04 5.9 4x4. I have recently started using 4x4 as it has started to snow and ice in Indiana. I noticed that after shifting into 4x4, my truck makes a knocking noise. The knocking is not very loud when accelerating, but when I let off the petal and begin to slow down the knocking gets louder. The 4x4 does work it just knocks. Should I be concerned? Is this normal?
 

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Put it on a lift a few inches off the ground. Have someone in the driver seat so they can put it in gear while you look and listen under the pickup.
 

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my guess is axle u joints
 

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I would second an axle you joint.
 

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If its a slower knock then its likely the axle u-joint. But...since you have a full-time 4wd, it should make some noise all the time.

I'm going to guess its the double cardan joint on the front driveshaft. When they get old and worn out they can knock. But DONT ignore it because when they're alerting you that means its not far from failure, and failure can mean damage.
 

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Mine was front drive shaft u joints. Y
 

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If its a slower knock then its likely the axle u-joint. But...since you have a full-time 4wd, it should make some noise all the time.

I'm going to guess its the double cardan joint on the front driveshaft. When they get old and worn out they can knock. But DONT ignore it because when they're alerting you that means its not far from failure, and failure can mean damage.
Yeah, what he said. If it breaks you do damage to wiring and cooling lines so inspect it right away. You can buy rebuild kits for the Cardon joint if you want to save a few $$.

Axle U joints will make a lot of noise in turns, not so much going straight. Also, check your T-case fluid cause if it gets low, the chain stretches and then can jump sprocket teeth. That makes a heck of a sound.
 

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:welcome:
knock is not normal, have you checked /changed oil in t-case, ATF+4 , any metal??
should be periodically using 4wd to keep gear/hub/shift components moving freely.
 

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If its a slower knock then its likely the axle u-joint. But...since you have a full-time 4wd, it should make some noise all the time.

I'm going to guess its the double cardan joint on the front driveshaft. When they get old and worn out they can knock. But DONT ignore it because when they're alerting you that means its not far from failure, and failure can mean damage.
3rd gens dont have full time 4wd , must be manually or electrically shifted, equipped with NV271 or NV273 Transfer cases, very good cases if properly maintained.
 

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3rd gens dont have full time 4wd , must be manually or electrically shifted, equipped with NV271 or NV273 Transfer cases, very good cases if properly maintained.
Yes they do... Model years 2002 through 2013 used full-time 4wd.
Full-time 4wd is when the only disconnect is the transfer case and the front driveshaft always spins at road speeds.
Part-time 4wd is when the disconnect is the transfer case and the CAD system (or free spin hubs) and the front driveshaft does not spin at road speeds.

And, the 4wd system should make no knocking noises...
 

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3rd gen cummins powered dodges are in 2wd, until you manually shift or electrically engage transfer case.

No power to front axle until transfer case is engaged.
 

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3rd gen cummins powered dodges are in 2wd, until you manually shift or electrically engage transfer case.

No power to front axle until transfer case is engaged.
That is how ALL 4wd systems work...
Re-read what I said previously about the differences in full-time vs part-time systems.
 

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You can word it however you want.
Truck is 2wd drive until you activate transfer case, then truck is in 4wd.
 

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You can word it however you want.
Truck is 2wd drive until you activate transfer case, then truck is in 4wd.
Not sure what you're point is...but I'm wording it correctly and accurately so that others reading the forum understand what the difference is and how it works.

You strangely want to argue for whatever weird reason. :confused013: Maybe you're thinking that "full-time" 4wd is the same as "all wheel drive". Its not...
 

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No, your confusing everyone,

The NV271 transfer case is a part-time transfer
case
with a low-range gear system. It provides three
operating ranges plus a NEUTRAL position. The low
range position provides a gear reduction ratio of
2.72:1 for increased low speed torque capability

The NV273 is an electronically controlled part-time
transfer case
with a low range gear reduction system.
The NV273 has three operating ranges plus a NEUTRAL
position. The low range system provides a gear
reduction ratio for increased low speed torque capability.
 

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All transfer cases are part-time unless they have an integrated differential or viscous coupler which allows them to be used as an AWD system. The entire 4wd system is either part time or full time based on the engagement of the front driveline. If the front driveshaft spins along with the front axle then its considered a full time system which has the disengagement at the transfer case. Thats what the 3rd gen trucks have. The ONLY disengagement is in the transfer case.

Yet if the transfer case has a differential or viscous coupler then it can be called either an AWD or full time transfer case. The trouble is the industry confuses people by forgetting the distinguishing differences between a part time and full time transfer case and simply labels their entire 4wd as they market it.

Example being, Jeeps Quadratrac 4wd which used a Borg Warner 1339 with an internal center differential. The Quadratrac could be used in both two wheel drive or full four wheel drive at all times because of the center differential.

Another example, Dodge called the part-time 4wd NP241 transfer case "shift on the fly." But then they also called the NP241 with full-time 4wd as shift on the fly too. Trouble is if you install a full time 241 in a CAD axle truck then you'll find it wont shift into 4wd "on the fly" because the part time 241 has a syncro ring to spool up the front driveshaft for engagement while moving, whereas the full time 241 does not. Why?...because the full time 241 does not need the syncro ring as the front driveshaft is always spinning at road speed therefore you can literally engage 4wd at any traveling speed.

I will admit that its overly confusing...but since Dodge has utilized the CAD in two different generation 4wd systems this is what we get.
 

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No Katoom that is not full time 4x4 it is a full time live front axle. Full time 4x4 is when the Transfer/case is always engaged in 4x4, either lock or AWD and/or a center differential in the TC. Full time 4x4 has no 2wd mode, always has power to front axle.
Front axle u-joints are always moving unless there is free hubs. Same for drive line if no CAD or hubs. Bad U-joints on either, or Cardin joint, may not make noticeable noise or vibration until TC engaged and under load, either accelerating or decelerating.
 

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Full time 4x4 has no 2wd mode, always has power to front axle.
Actually thats not accurate. And frustratingly wherever you look for such information, you'll get multiple different answers. Thus the confusion so many people have.
Full time 4wd can be used in either 2wd or 4wd. AWD is when all four tires are constantly getting power.
 

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That is how ALL 4wd systems work...
Re-read what I said previously about the differences in full-time vs part-time systems.
Not quite all. I have a 2005 Yukon and it is full time 4 wheel drive. Options are 4high, 4low and nuteral. It eats tires, but is a beast in snow......there are others like that too. And I’m sure there are sensors that affect how much the transfer case is engaged, but it’s full time.
 

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Lets address the OP for a change, don't give a hoot what ya'll want to call an engaged and disengaged transfer case. You're not being helpful at all.

Couple of questions:
1) Does the knock only happen in 4wd mode?
a) If so, will the knock happen in forward and reverse?

2) If the knock is not present in 2WD mode then inspect all the rotating joints, if you can giggle your front driveshaft the front slip joint will probably need greased.

3) If the knock is there in 2WD mode also, you'll need to inspect your flexplate. Flexplate knocks get louder with throttle input and quiet down under deceleration conditions. If they break in the right manner, and do not shatter into pieces, (I have pictures if you want to see) the huge washer will/may keep them from coming apart under mild driving conditions. Hopefully this is NOT your issue.
 
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