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Messages posted by: mavalos
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schwifi wrote: ........A vibration has developed in the last 6 weeks during vehicle operation between 45 to 55 mph when under cruising speed load. The vibration goes away (or is significantly less noticeable) under full throttle acceleration, and is not present under no-load (45-55 mpg and transmission in Neutral). Only seems to occur when cruising between 45-55 mph. No vibration when cruising at 70mph ........

Anyone have an Idea what this might be?


I have previously (less than a year ago) posted a similar issue here with my '05 Liberty CRD. I have the Eco and trans Tune. All the rotating masses (front axles, drivelines, etc) have been changed. Diagnostics at one shop has more recently revealed that after the rear driveshaft was removed, the vibration ceased. Note: a "special" provision was made that would not allow TCase fluid to escape where the DS mates to the TC. Consensus was that it may be differential or wheel bearings. Or possibly the clutches in the Trac Lok unit. Another person posted on LOST Jeep forum that he was experiencing the same problem and after installing new carrier & wheel bearings, the vibration went away. He did not reveal whether it was the carrier or rear wheel bearings that were bad and he didn't respond to me asking.

However, I'm not convinced that perhaps that his problem is the same as ours / mine. I even thought it may be bearing related in the TCase. I'm very weary of throwing even more $$ at something that can't be better or more definitively diagnosed. The TCase and differential parts are high dollar stuff to be guessing. However, I don't know how to narrow it down anymore as to one or the other. *frustrated*
GreenDieselEngineering wrote:Failed engine mounts might lead to more vibration. Maybe a driveshaft balance issue. I do not think the turbo would lead to this problem. Is the problem only with the torque converter in lock-up mode? Try the same speeds with OD off and see if the vibration changes.


Thanks so much for your input!

We've ruled out driveshaft(s). They were each removed with the same results.

Don't know about the TC in or out of lock-up mode, but don't know for sure. I think it locks up near 50 mph. According the the local TC shop here in town, after driving it, he doesn't seem to think it's the TC.

I've tried the same speeds with the OD on/off. No change. RPM's don't change the effect: at 45 - 53 mph on level ground with throttle pressure it vibrates / drones. Can feel it in the steering wheel. As soon as throttle pressure is released, the vibe and drone goes away. Some evidence of vibe / drone at above 55 mph but barely detectable.

One mechanic noticed the steering rack was a little loose. It was replaced at 60K miles. Not to say it's not worn out again due to the many off highway miles I put on it.

I agree that even though the motor mounts were replaced a couple years ago, I've decided to replace / inspect the passenger side this weekend.

The other culprit (steering rack bushings) could also be transmitting the vibe / noise, so while I'm under the Jeep I'll give it a real close look. There's a band-aid fix (found on LOST) for it by inserting some large flat rubber washers between the mounting surface and the rack.
Moore wrote:My liberty has the same vibration at 43-50. I am just about to do a new TC (because of shudder not vibration) and will let you know if it fixes this. I have been under the suspicion that it is the TC but haven't had a reason to change it until the shudder started (about 2000 miles after ECO tune). Also on a side note..... I have a local transmission shop and TC shop building a custom TC for me, they say there is no reason they cant build a TC just as strong as the Suncoast, including a billet front cover brazed fins and heavy duty springs on the internal for much less money.


Great to finally see a response to my post. As I mentioned, we have a well respected TC builder here also. I went back in his shop and was blown away at his equipment! Builds some TC's from billet stainless steel! He address the know problems of various TC's and doesn't try to sell you a "bullet proof" one unless it's what you want or need for your application.

At this moment my Jeep is at (yet another) shop for another opinion. The one thing they found so far is a loose rack that may be telegraphing sound / vibration.

Odd that you're experience as to MPH is exactly where mine come in. However, the TC guy didn't think it was the TC. If nothing is found by the Jeep shop, I may take it back to the TC shop and let him drive it again to verify.
mavalos wrote:I have both eco tune and trans tunes, purchased 04/2014 and 10/2014. I've developed a vibration (felt in the steering wheel) in the 40-50 mph range, only under throttle pressure not the coast side. I've ruled out any tires /driveline / axle issues. From what I've learned so far is that the TC may be causing it.

I put less than 7K miles / yr. and mostly for light to moderate off road use.

Factory REMAN motor has ~60K, odometer is 120K.

How can I test / know with reasonable certainty that is is in fact the TC? And if so what TC would be my best choice?


Bumping my post.

Took the Jeep to a long-time, reputable TC builder (Accerated Torque Converters) here in Grand Junction CO. He drove the Jeep and was pretty sure it wasn't the TC or the transmission making the vibration / droning noise. He suggested I take it to a driveline specialist which I did and he noted excessive lateral movement in the RF CV axle. Turns out that the replacement of that shaft I did a few months ago was not the correct part as it was for a gasser. They installed a new (correct) one along with a new inner axle shaft. Still no change in the vibration issue. They have no clue at this point of what to do.

Is it possible that the turbo would behave this way? I've run out of possibilities. VERY frustrating!!
I have both eco tune and trans tunes, purchased 04/2014 and 10/2014. I've developed a vibration (felt in the steering wheel) in the 40-50 mph range, only under throttle pressure not the coast side. I've ruled out any tires /driveline / axle issues. From what I've learned so far is that the TC may be causing it.

I put less than 7K miles / yr. and mostly for light to moderate off road use.

Factory REMAN motor has ~60K, odometer is 120K.

How can I test / know with reasonable certainty that is is in fact the TC? And if so what TC would be my best choice?
 
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