2025 Gladiator Rubicon with vibration after lift

[SingGladiator]

I have tried not to post and have searched to see if anyone has experienced this but I am truly at a loss and figure it is time. First off I will start with the build:

2025 Jeep Gladiator Rubicon
6.5" Evo enforcer level 4 lift (now with 4.5" springs) front control arm correction brackets
Apex Chassis Aluminum 2.5 ton steering with drag flip
Synergy track bar relocation bracket
Synergy sector shaft brace
Currie 5.13 gears
Adams 1350 front and rear drive shafts
Fox 2.0 shocks
Rear drive shaft carrier bearing drop
40x13.50x17 Nitto Trail Grapplers

I had all of this installed and took my keys on 1/9/2026. After completing the break in period for the gears We put in the front drive shaft and immediately there was a vibration. At this point it still had the 6.5" springs. The shop adjusted many things for months and I even sent the front drive shaft back to Adams who rebalanced it. I then brought it to another shop who had it and aligned and adjusted and finally we lowered with the 4.5" springs but the vibration is STILL there. The vibration is theere between 55-70 mph and also at low speeds approaching a stop you can hear the front drive shaft grinding...

It is a 2025 so the FAD is not there so this front shaft is contantly spinning. I have searched and searched and see so many 2024+ JL's and JT's lifted with 4.5 and 6.5 kits and not having the issues I have. I am being told there is nothing that can be done unless I get a free spin kit or go with a different (one ton) front axle that doesnt spin. I truly am at a loss as I am $17k ish into this build with just the above and labor and not to mention the time.

Anyone experience this? Successfully fix this? Any insight? I am at 6 degrees of castor and that is what they are telling me we should be at. The pinion angle was only reduced 3 degrees going from the 6.5" springs to the 4.5". the front axle was over 20 degrees opetation angle. I am not a technician nor a mechanic but I am truly just wanting my JT to work and be AMAZING...

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[Jteakus]

I'm going with driveshaft out of phase.
Does your JT have the FAD? Guessing it doesn't.

Edit: I see you do not have FAD. You are going to have to get your front pinion and front T-case output where their u-joints balance each other out. With 6 degrees caster and that much lift your pinion is likely looking down,
You have a really nice rig. A good offroad shop should be able to get you lined out.

 

[SingGladiator]

I'm going with driveshaft out of phase.
Does your JT have the FAD? Guessing it doesn't.

Unfortunately mine does not have the FAD from the factory... 2024 and newer they dont have the FAD...

 

[Jteakus]

https://4xshaft.com/blogs/general-t...sKyCK0x7f3lonz98PxQdPdod5afKE7VhoC7c8QAvD_BwE

 

[Stan H]

I have tried not to post and have searched to see if anyone has experienced this but I am truly at a loss and figure it is time. First off I will start with the build:

2025 Jeep Gladiator Rubicon
6.5" Evo enforcer level 4 lift (now with 4.5" springs) front control arm correction brackets
Apex Chassis Aluminum 2.5 ton steering with drag flip
Synergy track bar relocation bracket
Synergy sector shaft brace
Currie 5.13 gears
Adams 1350 front and rear drive shafts
Fox 2.0 shocks
Rear drive shaft carrier bearing drop
40x13.50x17 Nitto Trail Grapplers

I had all of this installed and took my keys on 1/9/2026. After completing the break in period for the gears We put in the front drive shaft and immediately there was a vibration. At this point it still had the 6.5" springs. The shop adjusted many things for months and I even sent the front drive shaft back to Adams who rebalanced it. I then brought it to another shop who had it and aligned and adjusted and finally we lowered with the 4.5" springs but the vibration is STILL there. The vibration is theere between 55-70 mph and also at low speeds approaching a stop you can hear the front drive shaft grinding...

It is a 2025 so the FAD is not there so this front shaft is contantly spinning. I have searched and searched and see so many 2024+ JL's and JT's lifted with 4.5 and 6.5 kits and not having the issues I have. I am being told there is nothing that can be done unless I get a free spin kit or go with a different (one ton) front axle that doesnt spin. I truly am at a loss as I am $17k ish into this build with just the above and labor and not to mention the time.

Anyone experience this? Successfully fix this? Any insight? I am at 6 degrees of castor and that is what they are telling me we should be at. The pinion angle was only reduced 3 degrees going from the 6.5" springs to the 4.5". the front axle was over 20 degrees opetation angle. I am not a technician nor a mechanic but I am truly just wanting my JT to work and be AMAZING...

Get a FAD motor actuator . Remove block off plate install wire to a switch in the cab flip it right before pulling 4wd drive lever in 4wd and vibrations will be gone. After you go back to 2wd flip switch FAD unlocks front axle . Simple as that

 

[SingGladiator]

Get a FAD motor actuator . Remove block off plate install wire to a switch in the cab flip it right before pulling 4wd drive lever in 4wd and vibrations will be gone. After you go back to 2wd flip switch FAD unlocks front axle . Simple as that

I am definitely not opposed to that! I can imagine some people have done that here.

 

[Stan H]

I am definitely not opposed to that! I can imagine some people have done that here.

Quite a few guys, several on here have and the FAD can be found online at reasonable prices and way the heck cheaper than any other option that you could do.

 

[SingGladiator]

I’m going to look into that for sure!

 

[Socket-Jockey]

Back when I did a custom lift on my 99 4Runner SAS conversion, I swapped in a D44 from an old Jeep Grand Wagoneer. I installed 12" coil suspension up front and to get the axle Pinion pointing towards the transfer case, without inducing Death-Wobble, I had to cut the inner knuckles from the axle tubing, rotate them accordingly, then reweld them. This actually worked VERY WELL, and allowed me to have vibration free miles of smiles. The guys who did the alignment were really impressed with the work, stating it was closer to spec (Grand Wagoneer) than a lot of vehicles they have worked on.

 

[Zachanadandy]

The stock rzeppa joints are very tolerable of the angles being off, which is why Jeep was able to eliminate the FAD without issues. U-joints on the other had are not. A cut and turn is the best way to fix it, but also very expensive. Adding the FAD is the budget friendly option. You'll still get vibrations at speed in 4HI, so be aware of that. Not really an issue unless you live in snow country and do a lot of highway driving in 4wd.

 

[SingGladiator]

The stock rzeppa joints are very tolerable of the angles being off, which is why Jeep was able to eliminate the FAD without issues. U-joints on the other had are not. A cut and turn is the best way to fix it, but also very expensive. Adding the FAD is the budget friendly option. You'll still get vibrations at speed in 4HI, so be aware of that. Not really an issue unless you live in snow country and do a lot of highway driving in 4wd.

Yeah see here in Florida I don’t need 4WD until the last second but most is 2WD. I see A LOT of 392 people talking about the FAD implementation. I am curious if there is a fuse or relay and a pigtail the Jeep left there for easy install?

 

[Zachanadandy]

Yeah see here in Florida I don’t need 4WD until the last second but most is 2WD. I see A LOT of 392 people talking about the FAD implementation. I am curious if there is a fuse or relay and a pigtail the Jeep left there for easy install?

That I don't know as both our JLUR and JT came with FADs. I'd imagine it would be fairly easy to find the wiring if its taped up above the axle from the factory.

 

[SingGladiator]

That I don't know as both our JLUR and JT came with FADs. I'd imagine it would be fairly easy to find the wiring if its taped up above the axle from the factory.

Time to investigate for sure!

 

[Zachanadandy]

Time to investigate for sure!

It's just a 12v motor so you could just put it on a manual switch. Power off the FAD is disconnected, power on its connected.

 

[Stan H]

Yeah see here in Florida I don’t need 4WD until the last second but most is 2WD. I see A LOT of 392 people talking about the FAD implementation. I am curious if there is a fuse or relay and a pigtail the Jeep left there for easy install?

No , it was eliminated from the harness.
The 4wd lever in trucks with it from Factory us what switches it on . . From what I learned it was removed . They didnt want anyone to have that ability.
Ya ask me its because they dont want anyone lifting these Jeeps

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