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Is selec track (or full time 4WD) inherently bad or weaker?

WXman

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So what makes the CV joint better than a U-Joint for 4A use?
Because of how u-joints are constructed the output shaft is continuously changing speeds versus the input shaft when the joint isn't straight, so each rotation your tires are speeding up and slowing down. How much of a change in speed there is is dictated by how far the wheels are turned. It's made worse by the fact that your two front wheels are rotating at different speeds from each other. When you use U-joints in a front axle it will “crow-hop” in turns while under power.
See the "Equation of Motion" section of this Wikipedia article for more info: https://en.wikipedia.org/wiki/Universal_joint.

CV (constant velocity) joints don't suffer from the variation in input vs output speeds that u-joints do, and thus don’t have crow-hop.
Ever tried to pull into a parking lot in 4H ?
Those joints bind like crazy even on snow.
They can't make sharp turns and having done driveshaft work for years, there are angles they are not supposed to make while under load.
4A may be engaged when making sharper turns. My truck almost slid into another vehicle as I tried to turn into a parking spot and the u-joints bound up. I had to back up and make another try - in 2.
I guess it makes sense considering that 4A could be used even on dry pavement. But let's face it, 99% of the time you're only going to use 4A or 4H either one if it's snowing or really nasty weather otherwise outside. So I think they could have gotten away with the stronger and more durable U-joint design. Oh well, not a major crisis as ALL of the IFS systems use CV joints and they hold up pretty well considering..
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ShadowsPapa

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Our hubs don't lock and unlock as you probably know.

Also, CVJs are stronger than U Joints. Nothing wimpy about them. Their weakness is that they need to run in a grease bath and depend on their boots. I've torn boots and caught it. I drove home and changed the boot and the CVJ never failed. (This includes taking everything apart, cleaning it thoroughly, regreasing and reassembling) So its reasonable that if you do an inspection after any serious off-roading you would be ok.

If you aren't going to be doing any kind of driving that might tear a boot they are functionally superior. Quieter, smoother, MUCH stronger at steering lock.

U joints fail also. They just fail differently. Often catastrophically. Whereas CVJs almost never fail catastrophically, leaving you on the side of the road or trail. I've broken U Joints on the back of my 66 chevy. It happens. Fortunately they are really easy to change on a driveshaft.
Ya basically beat me to it. I've not seen one fail to the point of leaving someone stranded UNLESS they ignore the torn boot and keep driving in the dust and dirt (and I mean even normal streets and roads have enough dust to destroy things)
They have precision fitting balls and channels and need to be kept clean.
I much prefer CV joints and that's what sort of joints are used in shafts that need to operate in extreme angles. The CV is constant velocity where a cross type joint speeds up and slows down when running at an angle.

But let's face it, 99% of the time you're only going to use 4A or 4H either one if it's snowing or really nasty weather otherwise outside. So I think they could have gotten away with the stronger and more durable U-joint design. Oh well, not a major crisis as ALL of the IFS systems use CV joints and they hold up pretty well considering..
Not necessarily - parking lots, in town, etc. U-joints pop and jerk in town and tighter turns and it's hard on them. They aren't made for angles like that.
CV joints are in all front wheel drive vehicles - don't see those people complaining and some put on a whole lot of miles. I've had several vehicles with CV joints in the front, only ever had one boot issue. I simply replaced the whole shaft and will rebuild the other shaft when I get a chance and have an entire spare.

I can turn this thing sharper than ANY Jeep with Cardan type joints up front and the joints run smooth as silk and it does zero damage to them.
The forces are also more evenly distributed over multiple hard steel balls with more surface area than those tiny needle bearings in a Cardan joint.

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Smoother operation. CV joints are, well, constant velocity and single u-joints are not.
That sucks that the Raptor was so much trouble. But it sounds like they Raptor was a fundamentally different system made by a different manufacturer.

Our hubs don't lock and unlock as you probably know.

Also, CVJs are stronger than U Joints. Nothing wimpy about them. Their weakness is that they need to run in a grease bath and depend on their boots. I've torn boots and caught it. I drove home and changed the boot and the CVJ never failed. (This includes taking everything apart, cleaning it thoroughly, regreasing and reassembling) So its reasonable that if you do an inspection after any serious off-roading you would be ok.

If you aren't going to be doing any kind of driving that might tear a boot they are functionally superior. Quieter, smoother, MUCH stronger at steering lock.

U joints fail also. They just fail differently. Often catastrophically. Whereas CVJs almost never fail catastrophically, leaving you on the side of the road or trail. I've broken U Joints on the back of my 66 chevy. It happens. Fortunately they are really easy to change on a driveshaft.
Thanks for the info. Makes sense.

I have to admit when I bought my Willys that came with the Selec-Trac option, I paid little attention to what all that entailed.
 

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There is a reason these are available in the aftermarket to replace the JT/JL OEM U-joint shafts.

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Jeep Gladiator Is selec track (or full time 4WD) inherently bad or weaker? cvj44-jl-fad_4


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Jeep Gladiator Is selec track (or full time 4WD) inherently bad or weaker? cvj44-jl_2
 

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There is a reason these are available in the aftermarket to replace the JT/JL OEM U-joint shafts.

With FAD
Jeep Gladiator Is selec track (or full time 4WD) inherently bad or weaker? cvj44-jl_2


Without FAD
Jeep Gladiator Is selec track (or full time 4WD) inherently bad or weaker? cvj44-jl_2
And if I ever had a front axle or joint failure, I will be going that route.
 

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And if I ever had a front axle or joint failure, I will be going that route.
Unless that failure is caused by you running huge tires or putting down more than stock power I’d probably go with the OEM CV axles. While the RCVs are really nice and super strong they require regular grease filling that the OEMs will not. Granted with good maintenance the RCVs will likely outlast the OEMs, but those OEM axles were designed to be invisible to the end user and should last a very long time on their own.

Any time I don’t have to spend working on my rig is time I get to spend using it.
 

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Unless that failure is caused by you running huge tires or putting down more than stock power I’d probably go with the OEM CV axles. While the RCVs are really nice and super strong they require regular grease filling that the OEMs will not. Granted with good maintenance the RCVs will likely outlast the OEMs, but those OEM axles were designed to be invisible to the end user and should last a very long time on their own.

Any time I don’t have to spend working on my rig is time I get to spend using it.
Good point. I run tires that stock axles can easily take and although I MAY talk to Dave about a supercharger in the far future, that's still not crazy stupid power going to the axles.
 

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There is a reason these are available in the aftermarket to replace the JT/JL OEM U-joint shafts.

With FAD
Jeep Gladiator Is selec track (or full time 4WD) inherently bad or weaker? cvj44-jl_2


Without FAD
Jeep Gladiator Is selec track (or full time 4WD) inherently bad or weaker? cvj44-jl_2
Oh my god. I've never seen anything like that. Is the boot rigid? Like a spherical bushing?

That seems to be the best of all world, though I assume they leak a bit. Is there a zirk fitting somewhere or do you have to "service" them occasionally??
 

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Oh my god. I've never seen anything like that. Is the boot rigid? Like a spherical bushing?

That seems to be the best of all world, though I assume they leak a bit. Is there a zirk fitting somewhere or do you have to "service" them occasionally??
The boot is fairly rigid - I believe it is made from a polyurethane type material. RCV claims it is less prone to off-road damage than a rubber boot.

Yes, they do leak a bit and throw grease.

Yes, there is a grease fitting and you have to service them regularly.

I installed RCVs on friend's XTerra, and the boots ended up splitting after a short time. This is apparently a common issue. I wasn't impressed.
 

dcmdon

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The boot is fairly rigid - I believe it is made from a polyurethane type material. RCV claims it is less prone to off-road damage than a rubber boot.

Yes, they do leak a bit and throw grease.

Yes, there is a grease fitting and you have to service them regularly.

I installed RCVs on friend's XTerra, and the boots ended up splitting after a short time. This is apparently a common issue. I wasn't impressed.
That's too bad.

Hopefully they will resolve that. Because the idea is pretty clever.
 

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Oh my god. I've never seen anything like that. Is the boot rigid? Like a spherical bushing?

That seems to be the best of all world, though I assume they leak a bit. Is there a zirk fitting somewhere or do you have to "service" them occasionally??
Those are axles from RCV. IIRC they came out around 2003 or so. The boot is essentially like a hard-ish sphere. There’s a zerk fitting on the end of the axle stub. You’re supposed to refill them every other oil change.

Edit: I see this was answered above. That’s what I get for not reading to the end!
 

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Hey guys,
Great board you have here. It’s nice to see people be able to disagree and still act like adults.
So, total rookie here but I think I’m getting close to pulling the trigger. I’ve narrowed it down to a Mojave or Rubicon. Still not sure if I’m going new or a damn close used one. From the start I had the full time 4WD in my head as being one of the options I had to have. Just made sense to me if you’re anywhere that gets snow. (In my uninformed mind).
I’ve looked at hundreds of vehicles online new and used and have literally seen it on probably 5 or less.
With it being such a cheap option why do people stay away from it?
I have it on my 2021 Mojave and I would strongly recommend it. I had to have it. My wife drives it too so she doesn't need to know anything about the gear box. I haven't had a real need for it yet but can tell you it's great in a driving rain storm and flooded roads. It's not even that expensive. I just leave it in Auto mode and there's no worries.

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I don't believe the Selec–Trac Full Time 4WD became available to order until the 2021 model year. I also don't think it's a common option for a dealer to add to a Gladiator they'll have sitting on their lot. You'd probably need to submit a factory order built the way you want or find a Glad that was built for someone who wanted full time 4WD.

With that, buying used right now will cost you a lotttt. If you can wait 10-16 weeks, do a factory order through one of the forum dealers (5-7% below invoice pricing).
I wish I would have knows this with the forum dealers as we ordered ours From Jones in MD back in November before finding this forum. And we just got the update it will be here 2.18.2022
 

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Just catching up - so much great info here. A few questions for you all....

after my experience with it tonig
So if I understood it correctly, the CV joints are on the outer axle shafts. However the front drive shaft still has U-joints? Or does that also have CV's?? If anyone had a picture that would be awesome to see...

Also - so all this talk about on road performance. Which is great of course. But how well would this transfer case hold up to actually being in 4H or 4L when truly off road? Does it actually 'lock' via gear into 4H or 4L? or is it still powered by viscus clutch like when it is in 4-auto? I think that makes a big difference? For someone strictly on road, then maybe no big deal but for some looking to be in situations requiring full use of 4H/L then strength and integrity would be important.

If in 4A it just uses clutches, and then is truly locked in 4H/L then this option is totally a no-brainer.

Except for one more aspect....electrical. How much of the electrical will be submerged if going through 30" of water? And salt from winter roads?


Rubicon and Mojave people talk as if all features are on all Gladiators...... no offroad+ on other models.
So what is offroad+ exactly? I thought the lower trims still had traction control and trail control or whatever that's called.
 

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The boot is fairly rigid - I believe it is made from a polyurethane type material. RCV claims it is less prone to off-road damage than a rubber boot.

Yes, they do leak a bit and throw grease.

Yes, there is a grease fitting and you have to service them regularly.

I installed RCVs on friend's XTerra, and the boots ended up splitting after a short time. This is apparently a common issue. I wasn't impressed.
The only time the RCV axles throw grease is if you over grease them. Once a year, 3 to 5 pumps of grease. Any more then that, you throw grease. Mine are 12 yrs old, and have 70,000 miles on them without any issues. I will be installing them on my new JTRD in about a year.
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