Driveline issue...Jeep bouncing

[Slewis12724]

I have a 2020 Gladiator Sport S with the max tow package

From March 2020 until March 2021 it rode great, no issues at all. In March 21 I had about 600 pounds on the back of the truck(overland build), all factory suspension except for a Terflex spacer leveling kit and air bags. One day in March 21, the truck just started bouncing. Nothing happened, it just started doing it.

Here is a timeline of what Ive bene through with this truck:

1. First I added some Rubicon factory shocks and nothing changed.
2. Next I added Falcon 3.3 shocks and a Hellwig rear sway. Nothing changed.
3. I removed my RTT and awnings(about 225 pounds), nothing changed.
4. Changed the tires from Falcon AT3Ws standard load to KO2 load range C, nothing changed.
5. Added a Clayton 2.5" ride right kit, nothing changed.
6. A local 4x4 shop added a driveshaft carrier bearing and a set of factory wheels and tires, nothing changed. They stated it is a driveline issue and referred me to a dealership.
7. My local dealership put the truck on a lift and could feel the bounce with it lifted completely off the ground(axles unsupported). I also observed the driver side rear tire wobbling while it was on the lift. The dealership added another set of wheels and tires on it and changed both rear axles and the driveshaft, nothing changed.
8. Jeep had me remove all of the weight on the back of the truck and a Jeep "engineer"(he was actually an engineer of being a dumbass) came in and checked the truck. That was dead end. He stated it was not bouncing at all even though the dealership said it was and it bounced all the way to the dealer and all the way home. As a result of removing the weight, the bouncing was reduced but it did not go away completely.
9. I removed all of the Clayton equipment from the rear end and put it back to factory. The harsh ride improved but the bouncing did not.

One crazy thing that makes no sense is that with lower tire pressures(anything below 34 pounds) will mave ake the bouncing a million times worse. I usually run with about 40 pounds per tire, which of cource makes the ride pretty harsh.

I recenlty added a set of Icon triple rate rear springs to help with the harshness. They helped, butu now the bouncing is worse.(I assume because the Icon springs are softer that the factory max tow springs).

I've called about 15 4x4 shops around the country and the truck has been in five different shops in the middle TN area and so far no one has had an answer. I also tried to get the truck replaced under TN lemon law( I meet all of the requirements and then some) and was turned down three times with no explanantion. I was told to hire an attorney if I wanted an answer as to why they keep saying no.

Does anyone have any clue as to what may be wrong with my truck? My opinion is that the entire rear axle assmebly from hub to hub, including the rear differential, needs to be replaced and not just the inner axle shafts but the dealership refused to do that.

I am open to any advice or suggestions at this point, outside of hire an attorney or get rid of the truck.(All lawyers refuse to help me and I refuse to get ripped off in the current car market)

****I apologize, but somehow I left out some of the most important details of what I'm experiencing with my Jeep. The bouncing starts around 35 mph, gets much worse at 40 mph, and goes away around 50 mph. I can drive around at 30 mph and barely feel it bounce. On some roads, such as concrete interstates, the bouncing starts immediately(Im already up to speed, past 50 mph when I get on these roads) and it continues until I exit that road.

When my truck was weighted down, it bounced the worst at 35 mph, since I took the weight off, the speed has changed to 40 mph.

So a couple of updates. Yesterday I had to replace my tires, again, for the second time in less than three years. My KO2s had less than 25k miles on them and were wearing improperly...cupping, inside wearing to much, uneven wear across...this was the same as the Falcon wildpeaks I had before. I got about 20k out of them, with the same wear issues.

Three days ago I towed my trailer for the first time since installing the Icon rear springs. The truck didn't bounce. The trailer was all over the place, but the Jeep didn't bounce. After unhooking the trailer, I drove the JT and the bouncing was back. It's odd that more weight directly over the rear axle made the bouncing worse, but weight behind the axle seemed to help.

I have been running Jeep Wranglers for many years and understand solid axles as I have owned CJ, TJ, JK, JkU and now I have a new 2023 Gladiator Rubicon all stock currently at 8000 miles and I have a similar issue that I have never seen before on any previous Jeeps. It started at around 2k miles and what I describe as micro bouncing that continues for multiple bounces that can occur anytime at speed under 50mph with even the smallest of bumps. The truck was in for warranty on this issue and they could not find anything, my plan is over the next couple of weeks to use my goPRO with a mighty mag under the vehicle in multiple locations to see if I can find the actual root cause. This truck has been flawless except for this issue. I am curious if others have this issue and just assume that this is expected with a solid axle vehicle. This may sound minor but it is annoying at this point, I have delayed my wheels and lift until I get this resolved.

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[ShadowsPapa]

It's not a solid axle thing. None of ours do anything like that and not should they. If it's a bounce and not a wobble, could be weak shock. How well balanced are the tires and where's tire inflation. Shocks prevent bounce.

 

[hickman785]

I have been running Jeep Wranglers for many years and understand solid axles as I have owned CJ, TJ, JK, JkU and now I have a new 2023 Gladiator Rubicon all stock currently at 8000 miles and I have a similar issue that I have never seen before on any previous Jeeps. It started at around 2k miles and what I describe as micro bouncing that continues for multiple bounces that can occur anytime at speed under 50mph with even the smallest of bumps. The truck was in for warranty on this issue and they could not find anything, my plan is over the next couple of weeks to use my goPRO with a mighty mag under the vehicle in multiple locations to see if I can find the actual root cause. This truck has been flawless except for this issue. I am curious if others have this issue and just assume that this is expected with a solid axle vehicle. This may sound minor but it is annoying at this point, I have delayed my wheels and lift until I get this resolved.

At one point mine bounced so hard it made me nauseous...and I never get nauseous...the dealership felt it and knew something was wrong but then the Jeep tech came in and said that there's nothing wrong with the truck and closed my case

 

[hickman785]

It's not a solid axle thing. None of ours do anything like that and not should they. If it's a bounce and not a wobble, could be weak shock. How well balanced are the tires and where's tire inflation. Shocks prevent bounce.

Mine has done it with 4 different sets of shocks, three sets of springs and about 6 sets of tires...less PSI and more weight on the truck made it worse, higher PSI and less weight made it better

 

[Proximo]

Mine has done it with 4 different sets of shocks, three sets of springs and about 6 sets of tires...less PSI and more weight on the truck made it worse, higher PSI and less weight made it better

Have your 6 sets of tires all been on the same wheels?

 

[hickman785]

Have your 6 sets of tires all been on the same wheels?

No...3 different sets of wheels...all terrains and highway tread...

 

[Proximo]

No...3 different sets of wheels...all terrains and highway tread...

Do you have wheel spacers and are they hub centric?

 

[hickman785]

Do you have wheel spacers and are they hub centric?

No spacers...I'm running factory steel wheels...the other wheels used were factory alloy wheels...one set came directly off of a new Gladiator while at the dealership

 

[Proximo]

No spacers...I'm running factory steel wheels...the other wheels used were factory alloy wheels...one set came directly off of a new Gladiator while at the dealership

Well, your thread was my Sunday morning read. Those were my only ideas. I will tell you that I had a 70" GTO Judge that cracked the frame behind the rear axle. It did the "bouncing" at highway speeds. So, I'd suggest getting into a full frame inspection, inside and out, checking for cracks and bad welds. Sorry for your loss when you burn that bitch to the ground, but also hope you find that "ah ha" moment. Good luck

 

[hickman785]

Well, your thread was my Sunday morning read. Those were my only ideas. I will tell you that I had a 70" GTO Judge that cracked the frame behind the rear axle. It did the "bouncing" at highway speeds. So, I'd suggest getting into a full frame inspection, inside and out, checking for cracks and bad welds. Sorry for your loss when you burn that bitch to the ground, but also hope you find that "ah ha" moment. Good luck

Lol...trust me it has definitely crossed my mind to run it off in the lake! I guess it's a good thing I moved away from the lake...I've had one ship suggest inspecting the frame and potentially welding in a support brace...that will be my next step

 

[Lost1wing]

If it was me, I would put it on jack stands or a lift. With a helper, I would inspect the entire driveline with the wheel rotating. A bent driveshaft or axle should be easy to see. Seems like something like this would have been found already, unless they don't really want to find it.

 

[hickman785]

If it was me, I would put it on jack stands or a lift. With a helper, I would inspect the entire driveline with the wheel rotating. A bent driveshaft or axle should be easy to see. Seems like something like this would have been found already, unless they don't really want to find it.

Yeah the dealership did that...we could see the driver side rear tire wobbling from across the room...the service manager agreed something is wrong...they replaced both rear axle shafts and the driveshaft...still did it...then the Jeep technician came in, said nothing was wrong and shut down everything...even with the service manager and technicians disagreeing with him...

 

[Lost1wing]

It is easy to find an issue and replace that part, never to check it again. Could they have put in a bad axle? Did they stop looking at other things when they found the bad axle?

 

[Volt0]

It is easy to find an issue and replace that part, never to check it again. Could they have put in a bad axle? Did they stop looking at other things when they found the bad axle?

That’s what I’m wondering, or did it just not actually get replaced. Jack stands, tires off, and treat it like a lathe with a piece of chalk. Brake caliper mounts?

 

[Freems]

sorry about your issues with the rig. It can be maddening. I’m going to suggest a long time consuming process that may help you find out what’s happening. You need to put it back Completely to stock, zero weight in the truck except you a small amount of fuel in the tank, I would even pull the spare tire out, then Force balance the stock wheels and tires and make sure the tire shop re-spin balances the wheels and tires to double check them. Watch them do the work in the shop. Then hit every type of road to set a base line. If it’s still is bouncing find a fresh dealership that you have not been to with the rig to have them drive it and look it over. This will give you a fresh perspective from a dealership on a 100% stock JT. Do not speak to them of any after market adds you’ve done in the past. If no bouncing, then add one after market piece at a time, road test after each add. IMO this is the only way to discover your issues. i hope this will help you solve the mystery.

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