FAD gone on 2023 Rubicon?

[Surfarch]

Any idea why the FAD would engage in 2WD? 2021 JLURxR here with 4:1 Rock–Trac Heavy–Duty Full–Time 4WD System. My front driveshaft is spinning in 2WD. The FAD engages around 1 MPH and disengages when I stop. I can spin the driveshaft by hand when parked. And yes, the FAD is there, not the cover plate.

Sponsored

 

[Zandcwhite]

Any idea why the FAD would engage in 2WD? 2021 JLURxR here with 4:1 Rock–Trac Heavy–Duty Full–Time 4WD System. My front driveshaft is spinning in 2WD. The FAD engages around 1 MPH and disengages when I stop. I can spin the driveshaft by hand when parked. And yes, the FAD is there, not the cover plate.

How are you testing that the fad is engaging? Just because the drive shaft spins doesn't necessarily mean it's engaged. Could be just enough drag from the gear oil that the spiders are spinning the ring gear and drive shaft as there's not much load there? I'd guess a camera under the jeep is the test method? You could unplug the FAD (yes you'll get a warning light but it won't hurt anything) and run the same test. If the driveshaft still spins and obviously the FAD isn't engaged as you've unplugged it you'd have your answer. If it doesn't spin with the FAD unplugged then you'd know it is in fact engaging and it would have to be some kind of software issue.

 

[Surfarch]

How are you testing that the fad is engaging? Just because the drive shaft spins doesn't necessarily mean it's engaged. Could be just enough drag from the gear oil that the spiders are spinning the ring gear and drive shaft as there's not much load there? I'd guess a camera under the jeep is the test method? You could unplug the FAD (yes you'll get a warning light but it won't hurt anything) and run the same test. If the driveshaft still spins and obviously the FAD isn't engaged as you've unplugged it you'd have your answer. If it doesn't spin with the FAD unplugged then you'd know it is in fact engaging and it would have to be some kind of software issue.

It's my assumption that is what is happening since it starts spinning at ~1 MPH. But I will try to unplug it and see if that still happens.

 

[mgroeger]

It's my assumption that is what is happening since it starts spinning at ~1 MPH. But I will try to unplug it and see if that still happens.

Have someone you don't care about lay under the Jeep and hold the driveshaft while you go forward and see if it moves.

 

[Surfarch]

I unplugged the FAD, in 2H, and it still spins. I am confused. Maybe it is supposed to spin no matter what?

 

[Zandcwhite]

I unplugged the FAD, in 2H, and it still spins. I am confused. Maybe it is supposed to spin no matter what?

Like I said, the FAD disconnects the passenger side axle shaft. The drivers side still spins the spider gears. Just the resistance of the gear oil is enough to spin the driveshaft. You could stop it from spinning with your hands but you'd have to hang under the jeep while driving. This seems like a case of looking for a problem when there isn't one...

Sponsored