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Let's talk front drive shafts

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Then let me throw a plug in there for non-greaseable u-joints...

A lot of people believe that having the ability to pump grease in greaseable u-joints every now makes them last longer. But in reality the non-greaseable are far superior to greaseable. Why...?
Because greaseable u-joints have one lightweight seal holding the grease which is designed to be weak enough to allow old grease to escape as new grease is pumped in. That weak seal also allows grease to escape during normal use and also allow contaminants and water to enter between service intervals. Anyone who's installed greaseable knows that the caps can fall off during inopportune times too while messing and moving things around. Thats how weak the seal is.

Non-greaseable on the other hand have three very firm seals which are tight enough that the cap snaps into place and doesnt come off unless you pull it off. You prefill them with a high quality synthetic grease and they'll likely last much much longer than greaseable will ever. And...you never have to pump grease into them with those stupid grease needles.

Lastly, the non-greaseable are stronger because they dont have the Zerk fittings which if not installed where the Zerk is pushed instead of pulled can become a weak link. Plus non-greaseable are usually solid whereas greaseable are drilled to allow grease a path to the caps.

If this seemingly goes against your current thought process of the two, then just remember that its far far more common to see non-greaseable u-joints on all rear OEM driveshafts which can go hundreds of thousands of miles without ever being touched. Thats all I install too...


I agree with this post 100%. And, it also answers your earlier question on why I would consider replacing a shaft in the first place. I consider these joints wear items. And I am especially uneasy with that factory grease joint in the shaft that I have never been able to grease to satisfaction. As hard as this truck is worked and as much time as it spends in the salt and grime here in PA, I would rather replace before it fails instead of after.
 
I agree with this post 100%. And, it also answers your earlier question on why I would consider replacing a shaft in the first place. I consider these joints wear items. And I am especially uneasy with that factory grease joint in the shaft that I have never been able to grease to satisfaction. As hard as this truck is worked and as much time as it spends in the salt and grime here in PA, I would rather replace before it fails instead of after.

Can I have your old one, Lol....with your maintenance schedule/experience, you will find/feel it starting to go, way before actual failure.
 
Can I have your old one, Lol....with your maintenance schedule/experience, you will find/feel it starting to go, way before actual failure.


I can't lie to you and tell you that I haven't felt a little speed related vibration up under my feet once in a while. I checked the shaft over last week when I had it out and there was nothing obvious and is still perfectly usable. But, it's time to start looking for one.
 
I can't lie to you and tell you that I haven't felt a little speed related vibration up under my feet once in a while. I checked the shaft over last week when I had it out and there was nothing obvious and is still perfectly usable. But, it's time to start looking for one.

Forgive me for not keeping up, but do you have a free spin kit? I feel that has helped prolong my driveshaft’s life, among other things.
 
I know 1410 is a Spicer size, and AAM sizes are a bit different. I know that one (the main?) reason 3 gen trucks and up have AAM components instead of the older trucks traditionally using Dana/ Spicer, is the result of a material supply/ contract dispute when DCX took over (married) Chrysler at the time of 3 gen development.
The front shaft Ozy posted has 1410 parts in it, and that raised a flag for me. So, to put my curiosity at rest, I’ve spent the last hour putting this chicken scratch chart together using a few websites including Denny’s Driveshaft, and Ft. Wayne clutch.
I’m pretty confident on the accuracy of this, and I hope we all agree. It’s obvious to me that shaft Ozy favors is a custom piece using Spicer sized joints.
Enjoy!
upload_2018-12-9_12-13-46.jpeg
 
Already an edit. The 1330 and 1350 are the same cross with different cup sizes.
1330= 1.062 also available in different cup sizes (X-Y)
1350= 1.188 only in this cup.
 
Forgive me for not keeping up, but do you have a free spin kit? I feel that has helped prolong my driveshaft’s life, among other things.


No, I don't have free spin hubs. I agree with you that it eliminates the vast majority of wear on that shaft. I use 4 wheel drive daily year around. So, I've decided to keep the components OEM and not have to get out and lock hubs as often as I would need to.
 
I can't lie to you and tell you that I haven't felt a little speed related vibration up under my feet once in a while. I checked the shaft over last week when I had it out and there was nothing obvious and is still perfectly usable. But, it's time to start looking for one.

I'm no fan of full time 4wd systems and Dodge eliminated the part time 4wd between 2002 and 2013. A full time 4wd means the only disconnect between the front driveline and the transmission is the transfer case. Therefore the front driveshaft spins at road speed all the time. This obviously is hard on the u-joints which are placed at steeper angles simply by virtue of being in a tighter confined distance between the front axle and transfer case.

Front driveshafts have three u-joints. One at the pumpkin yoke and two in the double cardan joint. U-joints by design are not constant velocity joints and create a harmonic pulse as they move. To stop that harmonic pulse there must an opposing u-joint of exact opposite angle to counter offset the harmonics. This is the concept of a double cardan joint.

The proper setup for a front driveshaft with a DC joint is to have the front pumpkin joint to be at 0* angle and let the DC joints take up the rest of the angle.

Now back to what Dodge did... The introduction of the 4 link suspension gave room for whats called the "death wobble". This is caused by incorrect caster setting not forward in the positive direction enough. That means rotating the pumpkin yoke towards the ground. The problem is that increases the u-joint angle which adds stress and lowers its service span.

So when Dodge eliminated the CAD part time 4wd front axle they also tried to increase caster by rotating the pumpkin in order to reduce suspension feedback issues. Combine this with a now full time 4wd system and you get a driveshaft which is likely to hum/vibrate as you drive down the highway.

Does this mean your u-joints are bad...? Maybe, maybe not. But nonetheless it was a stupid idea for Dodge to do this. And if you think you're alone then do a search for driveline vibrations on the 3rd and 4th gen trucks and you'll see thousands of people complaining about this annoying problem.

How do you fix it? Well you certainly shouldnt add a lift unless you know for sure that you'll be replacing front u-joints quite often. And you can hopefully run quality joints which will withstand the abuse of constant spinning at their set angles.

Other than that, I think this whole issue is exactly why Dodge brought back the CAD front axle design...
 
Sorry my OEM setup was absolutely perfect, zero vibs up to speed limiter, no DW at all, perfect.
There is no need for a CAD or FSH on good designed AWD setup.

The CAD is back only for EPA.
 
No, I don't have free spin hubs. I agree with you that it eliminates the vast majority of wear on that shaft. I use 4 wheel drive daily year around. So, I've decided to keep the components OEM and not have to get out and lock hubs as often as I would need to.

How many miles on your drive shaft now?
 
Sorry my OEM setup was absolutely perfect, zero vibs up to speed limiter, no DW at all, perfect.
There is no need for a CAD or FSH on good designed AWD setup.

The CAD is back only for EPA.

Feel free to do an internet search of the number of people who experience front driveline vibrations on the 3rd and 4th gen trucks. I'm betting they wouldnt agree with your assessment. And just for clarification in case anyone misunderstands, full time 4wd isnt the same as AWD.
 
My front shaft is 90-95% with negligible slack in the slip. With my hubs unlocked, I can inspect everything as if it were off the ground. No binds whatsoever.
That said, I can feel a difference in the floor when that shaft is spinning or not.
 
And just for clarification in case anyone misunderstands, full time 4wd isnt the same as AWD.

I always thought AWD was a layout like most crossovers have. A transverse powertrain with a non selectable “PTO” or miter box sending power to the back.
That was until my Durango RT said AWD on the hatch. That has a conventional, longitudinal powertrain and transfer case that runs front axle disconnected normally.
 
I always thought AWD was a layout like most crossovers have. A transverse powertrain with a non selectable “PTO” or miter box sending power to the back.
That was until my Durango RT said AWD on the hatch. That has a conventional, longitudinal powertrain and transfer case that runs front axle disconnected normally.

There's many different configurations for AWD systems. But however the driveline configuration, often the shafts use constant velocity CV joints and the have either center differentials or viscous / electric couplers to differentiate power percentages between the front and rear axles.
 
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