Regeared, now front driveshaft spins in 2WD

J

JTCamp

New member
Hey! New to the forum and what’s a better ice breaker than asking strangers for advice?

So I picked up my 24 JT Rubicon from a “reputable” Offroad shop on Friday after they regeared me to 4.88’s. On the drive home I had a noticeable whine from the front while coasting. Now today during freeway break-in I felt and heard a hum coming from the front and into the gas pedal. I came to the conclusion while driving that it felt as if the front driveshaft was spinning. So when I got to work I recorded under the vehicle and lo and behold the front driveshaft is spinning in 2wd.

My assumption is the FAD is not disengaging. I have no binding noises, I can shift into 4hi no problem, the only noticeable noise is the whine when coasting and the noise from the driveshaft spinning at highway speeds.

My question is: will this cause any damage to my transmission, front gears nd transfer case until it gets fixed? Should the shop replace the front gears or any other components when I request them to look at it? Any troubleshooting I can do at home that could potentially fix it without having to take anything a part?
 
Take it to the shop, could be an issue with the FAD or with the E-locker.

The FAD collar could be out of its groove on the shift fork or the Spicer E Locker can operate incorrectly if the sheet metal plate on the locker gets bent or isn't oriented correctly.

I would limit driving until the shop can take a look, depending on what is causing the issue you run the potential of making it worse.

It's not really a problem for the transfer case or gears to have the FAD hooked up and spinning the driveshaft, some people delete the FAD system altogether.
 
Check your front axle, 24-25’s from what we have seen, no longer have a FAD. The housing for it on the axle is still there, but there is no actuator. If you aren’t sure, post up a pic of the axle on passenger side where the FAD would be.

JTCamp said:
My assumption is the FAD is not disengaging. I have no binding noises, I can shift into 4hi no problem, the only noticeable noise is the whine when coasting and the noise from the driveshaft spinning at highway speeds.

My question is: will this cause any damage to my transmission, front gears nd transfer case until it gets fixed? Should the shop replace the front gears or any other components when I request them to look at it? Any troubleshooting I can do at home that could potentially fix it without having to take anything a part?
Click to expand...
To touch on these, your drivelines now spin faster with the new gears which can cause this along with running a lot of positive caster. The front components spinning in 2WD will not hurt anything as this is how most axles operate like in the JK. So you are totally fine and will just need to service that diff/gear oil as well when doing the rear.
 
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JTCamp said:
Hey! New to the forum and what’s a better ice breaker than asking strangers for advice?

So I picked up my 24 JT Rubicon from a “reputable” Offroad shop on Friday after they regeared me to 4.88’s. On the drive home I had a noticeable whine from the front while coasting. Now today during freeway break-in I felt and heard a hum coming from the front and into the gas pedal. I came to the conclusion while driving that it felt as if the front driveshaft was spinning. So when I got to work I recorded under the vehicle and lo and behold the front driveshaft is spinning in 2wd.

My assumption is the FAD is not disengaging. I have no binding noises, I can shift into 4hi no problem, the only noticeable noise is the whine when coasting and the noise from the driveshaft spinning at highway speeds.

My question is: will this cause any damage to my transmission, front gears nd transfer case until it gets fixed? Should the shop replace the front gears or any other components when I request them to look at it? Any troubleshooting I can do at home that could potentially fix it without having to take anything a part?
Click to expand...
Most 2024 Rubicons do not have FAD. Instead, the front axle always spins. Is your jeep also lifted? If it is lifted a lot you may need a new front driveshaft.
 
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