LOST JEEPS
http://www.lostjeeps.com/forum/phpBB3/

Crazy wheel/driveline wobble. Need help identifying. Prize!
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=1&t=38144		 Page 1 of 1
Author:  dgeist [ Thu Dec 11, 2008 6:45 pm ]
Post subject:  Crazy wheel/driveline wobble. Need help identifying. Prize!
So, some of you may remember my mentioning this issue before, but I'm still stumped, so here goes:

Since the day I bought the CRD new (with about 125 miles on it, it has 30k, now), I've had a strange wobble that I can only feel in my backside and I can only really SEE on a really smooth road as a slight cyclic sway of the body...really slight, and directly proportional to the vehicle speed. I have to describe it as one of the tires feeling like it's oval. It is most noticeable between 10 and 30 mph and not really at all above or below, so mostly in slow and go traffic when I'm most likely to think about things like wobbles in my wheels. Here are the things I've thought about and why i don't think that it is them:

Tires: I'm on the second set. The problem happened with both. Also, I had my tire shop put them on the super-duper road-force balancer last time and they didn't find anything abnormal

Air pressure: The issue persists at anything between 28 and 40 PSI. I've tried a couple ranges in between with no change.

Tire Defect...with both sets: Again, the road-force system is supposed to find stuff like this and it didn't.

Brakes: Although I do notice it under braking a little more, I think that's a symptom of my inertia. I can feel it under power going slightly uphil at 20 mph, too.

What do y'all think? Could this be a slightly off-flush hub or axle that just isn't enough to notice once I'm up to speed? Could something be bouncing out of balance in the driveline in that speed range and the harmonics just FEEL like they're coming from the wheels? It's driving me a little crazy (as I'm compulsive and can't stand not knowing) and I'm also out of my bumper2bumper soon and want to take care of it under warranty. Give me something to try... give me something to speculate about.

The winning solution gets a case of your favorite spirit (within reason) if you're ever through Atlanta :)

Thanks.
Dan
Author:  Jeepjeepster [ Thu Dec 11, 2008 7:05 pm ]
Post subject: 
So it does it ALL the time?

Sometimes when my jeep is cold(sat over night) it will hope for a little while like that. Figured it was the tires flat spotting then getting really cold, doesnt do it in the summer.

Also noticed it on certain types of roads. Usually really notice it when slowing down at red lights.
Author:  ATXKJ [ Thu Dec 11, 2008 8:27 pm ]
Post subject: 
How about a drlveline out of balance?

I know Jeep made some, not sure how it would feel.
Author:  InCommando [ Thu Dec 11, 2008 10:13 pm ]
Post subject: 
Well, a rotor can be mismanfactured to where it wobbles. That would be inertia & speed sensitive. The seat feel does lead you to the rear end. A driveshaft issue would not be out of the question.
Author:  jeepkj02 [ Thu Dec 11, 2008 11:28 pm ]
Post subject: 
what about rear u-joints?? that would cause a wobble or vibration.
Author:  letigre87 [ Fri Dec 12, 2008 12:33 am ]
Post subject: 
1. do you have a rear sway bar? mine had a little more wiggle in it after i took it off

2. are you driving on concrete or asphault roads? the wheel-base has alot to do with this, asphault roads are alot smoother, concrete roads tend to sag inbetween expansion joints, making for a real fun sometimes if they are spaced just right.

my jeep goes nuts down a new road they just put in, concrete, speed limit is 35 with stop lights, when slowing down and speeding up I would have a better ride offroad.

its like the anti liberty road, I look all around and see nobody else bajaing in the street except some pick-ups with no load in the back.
Author:  Guest [ Fri Dec 12, 2008 4:04 am ]
Post subject: 
Bent axle or a bent wheel, one of the two.


Also, road force balancers only work properly when the people operating them know what they're doing.

9 times out of ten, they do not. There is no replacement for an experienced tire person and a normal ol' balancer...they will find more with a tire than any road force balancer and dumbo with a wheel weight hammer ever will
Author:  dgeist [ Fri Dec 12, 2008 2:41 pm ]
Post subject:  Followups:
- I THINK it does it all the time (i.e. all speeds). I know that it's not weather/temp/time of day dependant. It's been there in all seasons and conditions.
- How can I test/validate a driveline out of balance?
- How can I check for a bent wheel / Axle on my own (i.e. not take it to a Stealership or a tire place necessarily)? Any visual Cues?
- Would I be able to observe the rotor warpage when the wheel is spinning? I assume that if it's bad enough to make this feeling occur, then I would have to be able to see the wheel move side2side a little when observed from the rear/front.

Thanks for the responses.
Dan
Author:  KY Liberty [ Fri Dec 12, 2008 3:14 pm ]
Post subject: 
This sounds a lot like what happened to mine. On mine, the factory LSD had broken and damaged the pinion bearing. I wonder is you might have a bad bearing?
Author:  john jr [ Fri Dec 12, 2008 7:08 pm ]
Post subject: 
ThunderbirdJunkie wrote:
Bent axle or a bent wheel, one of the two.




Exactly what i was going to say
Author:  flair11111 [ Fri Dec 12, 2008 8:50 pm ]
Post subject: 
i say a bad bearing most likely. i had this same feel in an old truck i drive. it all of a sudden started doing this one day and kept on for about 2 years. finally the rear wheel bearing gave up and the axle came out as i was taking a turn onto another road. got lucky.

had a new bearing pressed in and put it all back together, and it was the smoothest ride ild ever had.

ill take a case of yoohoos.
Author:  dgeist [ Sat Dec 13, 2008 12:15 am ]
Post subject: 
flair11111 wrote:
i say a bad bearing most likely. i had this same feel in an old truck i drive. it all of a sudden started doing this one day and kept on for about 2 years. finally the rear wheel bearing gave up and the axle came out as i was taking a turn onto another road. got lucky.

had a new bearing pressed in and put it all back together, and it was the smoothest ride ild ever had.

ill take a case of yoohoos.


Hey, now. The suggestions do need to actually lead to fixing the problem :) I'm still at a loss how to troubleshoot without dropping it off at a garage for them to play with for 2 weeks.

Dan
Author:  KY Liberty [ Sat Dec 13, 2008 1:14 am ]
Post subject: 
dgeist wrote:
flair11111 wrote:
i say a bad bearing most likely. i had this same feel in an old truck i drive. it all of a sudden started doing this one day and kept on for about 2 years. finally the rear wheel bearing gave up and the axle came out as i was taking a turn onto another road. got lucky.

had a new bearing pressed in and put it all back together, and it was the smoothest ride ild ever had.

ill take a case of yoohoos.


Hey, now. The suggestions do need to actually lead to fixing the problem :) I'm still at a loss how to troubleshoot without dropping it off at a garage for them to play with for 2 weeks.

Dan


Maybe you should just click your heels together 3 times then and say "There's nothing like a perfectly working Jeep."

Sorry, just couldn't resist. :)

We're trying to help you out by comparing your problem to ones we've experienced. No one knew what the real problem was with mine and it was misdiagnosed by two places before I took it to my transmission and differential guy. He's a genius with Jeeps, and he wasn't even positive about what the problem was until he tore apart the rear differential. I was really lucky that I had decided to use something wrong as an excuse to upgrade to a DTT. Otherwise I would have ended up ordering one while the KJ was on the lift. I must say, it still sounds extremely similar to the bearing problem I was having.
Author:  Guest [ Sat Dec 13, 2008 3:40 am ]
Post subject: 
Jack up the rearend, chock the front wheels, and put the Jeep in gear and watch both rear wheels.
Author:  dgeist [ Sat Dec 13, 2008 10:20 am ]
Post subject: 
ThunderbirdJunkie wrote:
Jack up the rearend, chock the front wheels, and put the Jeep in gear and watch both rear wheels.


I'll try that and possibly snap a video of it to see what you guys thing. I really do appreciate everyone's suggestions, just that I have a little one and not much time to "play" with the jeep, and as far as "she who must be obeyed" is concerned, if the car isn't smoking, stalling, or the radio isn't working, it's not important enough to trump the rest of what's going on in our lives. I have to choose the things to troubleshoot carefully since I don't have much time to do it.

Dan
Page 1 of 1 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/