On a Mission: 50mph rumble

[duderz7]

Did u have all u joints replaced in rear shaft? When I I replaced mine rear most one went to crap a week later and was replaced again, and all is good now, Maybe you got a bad one like I did.

 

[SAString]

Did u have all u joints replaced in rear shaft? When I I replaced mine rear most one went to crap a week later and was replaced again, and all is good now, Maybe you got a bad one like I did.

I replaced both U joints. Interestingly, a manager at the shop that did the balancing said I shouldn't be using greasable U-joints, since they need tolerance for the grease to flow into and around the needle bearings. Apparently, sealed U joints are higher precision and have less "slop". Maybe that will be my next (lowest cost) alternative. Hopefully I won't require a re-balance.

 

[SAString]

OK, I've put over $3,000 into this Liberty, mostly throwing parts and labor into the vibration at 50 mph issue. Just did a new steering rack, tie rods, AC clutch, new brake rotors and rear drums. It still vibrates like day one, so we're missing something people! Now i'm thinking motor or transmission mounts, or even Transfer case rebuild.

Has anyone solved this issue that can provide a high confidence direction?

 

[Charlesthe2nd]

Check the front differential mount bushings as well, they might be shot along with the motor mounts. I replaced mine with energy suspension bushings and it made a big difference.

 

[SAString]

Check the front differential mount bushings as well, they might be shot along with the motor mounts. I replaced mine with energy suspension bushings and it made a big difference.

Thanks Charles2. I'll check those bushings and mounts. Where do I buy "energy suspension bushings" vs the stock parts? I've read on the 2005 diesel that they made a lot of NVH changes including "hydraulic motor mounts." But I haven't found if they fit the '02 3.7L. Is it possible to provide a link?

 

[Phil + Neela]

I don’t remember if you ever had the tires rebalanced, but when I was tracking down a vibration it turned out to be an unbalanced tire. Their weird part is that it never felt anything like the unbalanced tires I had in the past.

A combination of front driveshaft rebuild and a tire balance fixed mine.


Also, if it only vibrates at speed and not at a certain RPM, you can rule out the motor mounts. Plus, the transmission shouldn’t vibrate at all, so I would be surprised if it (or its broken mounts) are causing this unless it’s about to grenade.


Sent from my iPhone using Tapatalk

 

[SAString]

Thanks P + N:
Yes, I replaced the rusted stock steel wheels and hubcaps with '08 Liberty aluminum wheels, but had the existing BFG Longtrail Tires reinstalled. Balanced them at that time, plus had them balanced again on a Hunter machine at another shop just to be sure. I replaced the front driveshaft already.

 

[SAString]

Update: Steering rack bushings were worn so replaced. Replaced the LH CV axle and lower ball joint. Vibration still there!

I'm now focusing on the Transfer Case. Anyone go threw a rebuild, or replacing output bearings, find it helps the 50mph vibrations?

 

[RenKJ]

Update: Steering rack bushings were worn so replaced. Replaced the LH CV axle and lower ball joint. Vibration still there!

I'm now focusing on the Transfer Case. Anyone go threw a rebuild, or replacing output bearings, find it helps the 50mph vibrations?

If you have the 231 there should be a fair bit of rebuild guides on youtube, out of curiosity did you have to fully disassemble steering to replace steering rack bushings?

 

[SAString]

If you have the 231 there should be a fair bit of rebuild guides on youtube, out of curiosity did you have to fully disassemble steering to replace steering rack bushings?

Thanks RenKJ: Yes I have a NP231J. I've found many of the online rebuilds, although I'd like to learn if it was going to help the vibration before I go to that extent. I haven't found any concrete answers anywhere. I actually replaced the entire rack after I saw some seals were leaking. Yes, new tie rods on the ends also. Big job but was able to do it myself thanks to YouTube. Had to pay for an alignment though. You should be able to replace the bushings without taking out, but will need to remove the two mounting bolts, hammer the tierods out and release the steering shaft at the coupling. You wont need to remove the rack to push out the rubber bushings and put everything back together. Looking back on that weekend, that was the easy part.

 

[Charlesthe2nd]

SAString sorry for the late reply. I completely missed your reply. As for the specific bushing that was used, I'm not sure which one it is, because the shop installed it. It made a difference in the vibration for me, but that was a front end vibration that was only bad over bumpy roads, due to the mounts being shot. Here is a link for energy suspension bushings. You'll have to match the closest looking bushing I guess.

I'm currently dealing with a front end clunk that can be felt at both a creep and at 50mph. Your tenacity to find the solution to your rumble is lighting the fire for me. I'm going to start pulling my front end apart as soon as I have the time.

 

[SAString]

SAString sorry for the late reply. I completely missed your reply. As for the specific bushing that was used, I'm not sure which one it is, because the shop installed it. It made a difference in the vibration for me, but that was a front end vibration that was only bad over bumpy roads, due to the mounts being shot. Here is a link for energy suspension bushings. You'll have to match the closest looking bushing I guess.

I'm currently dealing with a front end clunk that can be felt at both a creep and at 50mph. Your tenacity to find the solution to your rumble is lighting the fire for me. I'm going to start pulling my front end apart as soon as I have the time.

Hi Charles2nd:
I bought a rebuilt steering rack from Detroit Diesel. It came with new bushings luckily. High core-charge, but it worked out well. I haven't experienced any "clunks" yet, so not sure how to help. Is it while turning?

 

[Cardhu]

https://jeepinbyal.com/liberty-2002-2007-kj/y-link-extension-fits-2-5-4-lifts.html

did you buy one of these when you did you lift? I never did one on mine and the drive to the dealership after i put it back to stock when i sold it was quiet and vib free leading me to believe it was all pinion angle.

Does your vib change when you freshly grease the u joints? If so the ujoints might be done already as it appears to have gotten worse.

 

[Charlesthe2nd]

Hi Charles2nd:
I haven't experienced any "clunks" yet, so not sure how to help. Is it while turning?

I hope you don't get any clunks, they are hard to address sometimes. No, its a consistent thump as I move forward, i.e. you can hear it every revolution of the tires. I think my intermediate shaft is shot, or it is my front driveshaft. Either way, lots of things to take apart to figure it out. Still don't have the time to address it either.

 

[SAString]

Making Progress

I replaced my RH CV Axle last weekend. It really helped with the vibes and noises up front. Very quiet now. I'm surprised the shop that replaced the Intermediate Shaft several months ago, didn't notice any issues with the RH CV Axle when they replaced the Intermediate shaft (I never saw the old shaft, so couldn't tell you what condition it was in). But, I replaced the CV axle so got a good look at everything. I was shocked to see they didn't use ANY grease on the splines. The old CV (female) spines were rusty and dry when I pulled the Axle. I didn't notice any wear/damage on the male spines of the new Intermediate shaft, but that can't be good practice. Makes me wonder what the diff end looks like! Long story short. Still Vibes at 50!

 

[SAString]

Update: No clip on the Intermediate shaft! I've taken the Liberty back to 4WP after it seems the Intermediate shaft and RH CV Axle have self destructed each other without a retaining clip to hold them in place. They offered to fix it under warranty. I also asked them to check the pinion angles while they were at it. I'll report results tonight after I give it a drive at highway speed.

 

[SAString]

Vibe still there!

4WP was very good about making sure my Jeep was done correctly and stood by their word to correct the issue. All new shaft and RH axle parts, put together with grease and clips.

But, it still vibrates at 50mph. It's got to be something that I've already been over once. Maybe tire balance or wheel run-out. Maybe look at both the front and the rear shaft balance again.

 

[SAString]

Back on here again to provide an update. A good tire balance with a Hunter machine found 1.5 oz of imbalance, which helped a little. Last weekend, I removed the new front drive shaft and it's actually tolerable, still vibrates slightly from 47mph to 62mph but clears-up after that. I feel OK about driving it at highway speeds now. But, I no longer have a front shaft and no 4WD. The front driveshaft is new, but could be out of balance (has weights welded on so should be OK). After everything I've read and done, I'm beginning the think the problem is in the front output bearings of the transfer case. So many people have a very similar issue and have spent thousands trying to solve the vibration, but few have gone to the effort of rebuilding the transfer case. At least no one has followed up by providing a solution to the 50mph vibration issue.
I think all KJs, if driven in 4WD on dry pavement with the NP231J TC (whether intentional or not) put excessive strain on the transfer case and eventually damage the bearings and chain, adding slop and vibrations. After double checking the balance on BOTH my driveshafts, I'm rebuilding my transfer case. Any recommendations on what brand of Kit to buy?

 

[Myke]

231J master rebuild kits and sye conversions.

JB Conversions, Inc. <-- this is a link

If you're pulling it apart and are lifted now is a good time to do the sye kit. You can also find a 231C at a junkyard and use it to upgrade to 6 pinion planetary gear.


Also unless your tcase has fulltime 4wd you should NEVER be in 4wd on dry pavement. This goes for any 4wd vehicle not just a Liberty. The 231J is a strong t-case.

 

[SAString]

OK, now I just did something stupid. 4Wheel Parts did an inspection and tells me my rear shaft needs to be re-checked for balance. That's got to be it right? KJ up on blocks, rear and front shafts removed and sent to Inland Truck parts and Service. Two days go by and I get the call, "You need new shafts. The rear is totally out of runout tolerance and your spline teeth are worn. $629 if you want it before the weekend because we need to FedEx the parts overnight. Plus, that front shaft you brought in is junk, send it back for warranty." OK, Whatever, I just want this this to stop vibrating!...

For $629 I could have rebuilt the TC and bought a new SYE kit and solved this mess. The new shiny custom shaft, harmonic balancer and spine yoke did nothing. Stupid me! It still Vibrates!!! !I feel like an idiot and a fool. Now the passenger front it is clunking and I'm told it's the Upper Control Arm. I'm losing my sanity and salary!