Why Is FAD Capability Lost with JPP 'Ultimate Dana 44 Advantek' Crate Axle Assembly?

[MOPAR Boy]

I keep reading that the JPP 'Ultimate Dana 44 Advantek' crate axle assembly for the Rubicon Gladiator is the EXACT SAME axle assembly as is factory installed on the Gladiator Rubicon (including the Eco diesel). If so, may I ask 2 questions?

1-Why is FAD capability lost?! and,

2-What gives on the Rubicon's front diff locker capability when replacing the factory Rubi axle with this crate axle? In the JPP catalog, it says this crate axle assembly comes '...prewired with the electronic diff lockers already installed...' The diff lock wiring is already there, and the Gladiator Rubicon already has the front diff locker switch present, so I'm confused (which isn't hard to do!).

Thanks, in advance, for any kind help on this. Ideally, perhaps someone who owns a JT, and who has actually laid out the $5k (not including insatllation cost) for this crate axle, can weigh in on these 2 questions?

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[sdk131]

1. FAD - the new axle does not even have a FAD installed (passenger side axle shaft is not a two piece).....so that is why you lose it .

2. My guess is different connectors and switching.

Here is a longer thread on the JL wrangler forum...the answers may be over there. https://www.jlwranglerforums.com/fo...ce-axles-jpp-ultimate-dana-44-advantek.17639/

 

[j.o.y.ride]

FAD is something Jeep had added to increase mileage for EPA. The raw axle not sent to Jeep will be identical with the exception of the Jeep specific spec of FAD.

After market, Dana isn't going to make a FAD axle for several reasons, including ECU compatibility of the various vehicles it may find itself in, and no off roader who buys it for a build would desire it.

 

[brianinca]

The FAD is a weak point in the axle, they probably figured it was NOT what people adding a locking D44 to their Jeep would want.

 

[MOPAR Boy]

1. FAD - the new axle does not even have a FAD installed (passenger side axle shaft is not a two piece).....so that is why you lose it .

2. My guess is different connectors and switching.

Here is a longer thread on the JL wrangler forum...the answers may be over there. https://www.jlwranglerforums.com/fo...ce-axles-jpp-ultimate-dana-44-advantek.17639/

So, for a 2021 Gladiator Rubi JT, there is no reason to install the crate axle, and inmsterqad simply instal a new ring and pinion to acheive 4.88? Why the heck is the passenger side not a two piece assembly? Why did Mopar and Dan decide to do this? I guess it's cheaper, but look at such a huge capabiolity sacraficed, and for what?

FAD is something Jeep had added to increase mileage for EPA. The raw axle not sent to Jeep will be identical with the exception of the Jeep specific spec of FAD.

After market, Dana isn't going to make a FAD axle for several reasons, including ECU compatibility of the various vehicles it may find itself in, and no off roader who buys it for a build would desire it.

But I have read a ton of articles saying the AdvanTEC/Dana 44 Ultra without the FAD has quite a bit of noticeable drag that is predisely why the FAD is designed to eliminate. I am not worried about losing 0.5mpg, but I sure don't like the idea of feeling like I'm driving my Ford truck with manual hubs set to On, and in 2WD. You could feel the drag come into play when you turned the hubs On in 2WD, and when you turned them Offf, you could feel the drag stop. Night and day, and this is what I am reading about the Ultra 44. My use is 50/50, On road/Off raod, so this is a factor for me, especially at 70mph+. I'm also worried about wear problems on the front suspension, given the no FAD situation whilst running big 37's, what with all their unsprung weight, gigantic size, and exacerbated by my -32 offset wheels (torque). Not really wanted to have to haul my JT to go have fun off road!

 

[j.o.y.ride]

So, for a 2021 Gladiator Rubi JT, there is no reason to install the crate axle, and inmsterqad simply instal a new ring and pinion to acheive 4.88? Why the heck is the passenger side not a two piece assembly? Why did Mopar and Dan decide to do this? I guess it's cheaper, but look at such a huge capabiolity sacraficed, and for what?

But I have read a ton of articles saying the AdvanTEC/Dana 44 Ultra without the FAD has quite a bit of noticeable drag that is predisely why the FAD is designed to eliminate. I am not worried about losing 0.5mpg, but I sure don't like the idea of feeling like I'm driving my Ford truck with manual hubs set to On, and in 2WD. You could feel the drag come into play when you turned the hubs On in 2WD, and when you turned them Offf, you could feel the drag stop. Night and day, and this is what I am reading about the Ultra 44. My use is 50/50, On road/Off raod, so this is a factor for me, especially at 70mph+. I'm also worried about wear problems on the front suspension, given the no FAD situation whilst running big 37's, what with all their unsprung weight, gigantic size, and exacerbated by my -32 offset wheels (torque). Not really wanted to have to haul my JT to go have fun off road!

Why would you ever consider swapping an entire axle assembly to only go with the one you already have (FAD aside) to simply have different gearing? Just swap the gears. Maybe if you were going to be gaining the e-locker but you have a Rubicon.

And it's not so much that the crate axle is draggier, it's that the FAD equipped axle is a little freer.

 

[MOPAR Boy]

Why would you ever consider swapping an entire axle assembly to only go with the one you already have (FAD aside) to simply have different gearing? Just swap the gears. Maybe if you were going to be gaining the e-locker but you have a Rubicon.

And it's not so much that the crate axle is draggier, it's that the FAD equipped axle is a little freer.

Unfortunately, JPP/Mopar do not have a ring and pinion re-gear kit available for the front axle. They do sell a JPP kit to re-gear the rear axle. This would mean I’d have to go non-JPP aftermarket for the front axle. In turn, my dealer will not install it. Meaning aftermarket parts, let alone installed by some shade tree mechanic, so buh-bye power train warranty on my brand new JT. So far, everything is being done via my dealer, including all parts and installations, so my warranty is good.

 

[j.o.y.ride]

Where do you live? I trust my local 4x4 shop to do that kind of work WAY WAY WAY more than any dealer. Spicer goes deep to 5.38 on that axle, front and rear... though the pinion gets tiny and becomes a weak point.

 

[NachoRuby]

Unfortunately, JPP/Mopar do not have a ring and pinion re-gear kit available for the front axle. They do sell a JPP kit to re-gear the rear axle. This would mean I’d have to go non-JPP aftermarket for the front axle. In turn, my dealer will not install it. Meaning aftermarket parts, let alone installed by some shade tree mechanic, so buh-bye power train warranty on my brand new JT. So far, everything is being done via my dealer, including all parts and installations, so my warranty is good.

Front:
https://www.moparonlineparts.com/sku/77072409.html
Rear:
https://www.moparonlineparts.com/sku/77072410.html

 

[MOPAR Boy]

And it's not so much that the crate axle is draggier, it's that the FAD equipped axle is a little freer.

I’m not understanding your logic here. If the “FAD equipped axle is a little freer,” then that’s exactly my point. I read a lot of posts saying that the non-FAD equipped axle causes noticeable drag, especially at freeway speeds. I assume another way of saying that is to say it “felt freer with FAD.” Either way, seems like essentially the same observation.

 

[j.o.y.ride]

You can probably sell your Rubicon axles for $2,500 each, they have 4.10 and e-lockers. Problem is the new axle is $4,900 without labor. It's easier labor than gears, but labor. Call it $6,000 with taxes and labor. If your warranty is worth $3,500 go with the new axle but it's going to have no FAD and IDK what the dealer will even do with that then. Dealer installed FAD delete probably doesn't exist.

 

[j.o.y.ride]

I’m not understanding your logic here. If the “FAD equipped axle is a little freer,” then that’s exactly my point. I read a lot of posts saying that the non-FAD equipped axle causes noticeable drag, especially at freeway speeds. I assume another way of saying that is to say it “felt freer with FAD.” Either way, seems like essentially the same observation.

My point was that there are 2 ways to look at it. Either the traditional one is tighter, or the Jeep is more free. But since the traditional is the baseline, I look at is as the Jeep is extra free.

 

[j.o.y.ride]

Front:

https://www.moparonlineparts.com/sku/77072409.html
Rear:
https://www.moparonlineparts.com/sku/77072410.html

Is it a full install fit for it or just the ring/pinion? If he's going dealer service they would need the full install or master kit available as a SKU.

 

[NachoRuby]

Is it a full install fit for it or just the ring/pinion? If he's going dealer service they would need the full install or master kit available as a SKU.

Here is what's included, but he might have to go piecemeal.

Ring Gear
1 Pinion Gear
10 Ring Gear Bolts
1 Crush Sleeve
1 Oil Seal
1 Pinion Nut

 

[MOPAR Boy]

My point was that there are 2 ways to look at it. Either the traditional one is tighter, or the Jeep is more free.

OK, gotchyuh. I am a bit conflicted, though, as it would be so nice and bulletproof to get rid of the FAD, in terms of a bit more strength up front, and no box to bust. But more importantly, I have read that going in/out of 2WD/4WD is so much quicker and smoother without the FAD mess. I test drove tow 2021 JTDR's at my dealer recently, and I had to pull on the 2WD/4WD lever like a son-of-a-bitch whilst driving like 10mph to get it to engae and disengage from 2WD/4WD. Same thing happened with 2 different JT's. Don;t get me wrong, it wasn't like it didn't work, by any means. It was just really dang stiff, and I had to really yank on it. From what I have read in some posts, this will not be the case with no FAD?

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