Sudden onset of jumping / loping feeling, like tires are egg-shaped

WestCoastDan

WestCoastDan

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'03 SE Wrangler. 4.0 Auto w/ 180K miles.
Had the vehicle serviced while I was out of town last week.
Work done included a new fuel pump, plugs, power steering hose, oil pan and valve cover gaskets, and a new transmission mount.

Seems like everything was done well, but now I have a serious drivability issue.
Even at low speeds on flat ground, the entire Jeep feels like the tires are oval-shaped, creating a bounce that you can feel through the seat.

The first thing I did was check & reset the air pressure to 29 PSI on all 4 (plus the spare).

No change. It still lopes like a hay wagon with egg-shaped wheels.

Any ideas other than to have the wheels all rebalanced?
 
I spoke w/ the guy and he said the only thing they removed was the rear hitch to dop the tank when the installed the new fuel pump.
It makes me think that either the new trans mount is wonky, or the driveshaft is somehow out of balance.
So weird.
 
Really need more info. Lift? Age of OEM parts? My issues came on in a couple weeks. A$$ end was bobbling. Up and down left and right. I put a bandaide on with shocks and stabilizer bushings and sway bar bushings on the rear. Helped. But, still wore out suspension on my 05’ LJ Sport 4” lift.
 
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How bad is the bounce you're having? Bad enough you couldn't drive it comfortably on the highway? Trying to gauge the level of bumpiness that you're feeling.

If it were me I'd throw the axles on stands and spin the tires looking for any thing off.
 
Bad balancing would be more like a shake than a egg shaped lope. Check the lugs for one and then jack up each wheel till the trie is just barely off the ground. Rotate and watch for big differences in the space between the tire and ground. It do sound like a tire is coming apart. #2, check the D/Shaft. It wouldent be the first time a shop screwed up a vehicle.
 
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Leaning towards the broken belt theory since last month I hydroplaned and bounced against/over a curb.
I inspected the tires following that event, but the damage may not have been immediately evident.
This is not our DD, so it sits a bit and the thing could have broken while it sat at the shop last week.
 
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WestCoastDan said:
'03 SE Wrangler. 4.0 Auto w/ 180K miles.
Had the vehicle serviced while I was out of town last week.
Work done included a new fuel pump, plugs, power steering hose, oil pan and valve cover gaskets, and a new transmission mount.

Seems like everything was done well, but now I have a serious drivability issue.
Even at low speeds on flat ground, the entire Jeep feels like the tires are oval-shaped, creating a bounce that you can feel through the seat.
Click to expand...

I've stated here many times over the years that I don't believe in coincidences when it comes to vehicle issues. If everything was fine, you had service done, and something is immediately wrong, it's almost always related to the service done. Of the list you provided, the new transmission mount is the only thing in my mind that can cause the vibration problem you mention. I'd be investigating that more if it were my Jeep. Ideas to investigate:
  1. Was a crappy mount installed that's two soft? Too stiff?
  2. Did the installation raise or lower the transfer case, changing your pinion angle?
  3. Was a bolt left loose?
  4. Walk through what was done with the tech who did the work, looking at everything touched. Sometimes, a tech will mess with something unexpected, so you never look there...
 
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WestCoastDan said:
Leaning towards the broken belt theory since last month I hydroplaned and bounced against/over a curb.
Click to expand...

OK, so disregard my no coincidences theory in this case. This new information changes my response. A bent wheel or damaged tire can definitely cause your troubles. Start there!
 
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sab said:
I've stated here many times over the years that I don't believe in coincidences when it comes to vehicle issues. If everything was fine, you had service done, and something is immediately wrong, it's almost always related to the service done. Of the list you provided, the new transmission mount is the only thing in my mind that can cause the vibration problem you mention. I'd be investigating that more if it were my Jeep. Ideas to investigate:
  1. Was a crappy mount installed that's two soft? Too stiff?
  2. Did the installation raise or lower the transfer case, changing your pinion angle?
  3. Was a bolt left loose?
  4. Walk through what was done with the tech who did the work, looking at everything touched. Sometimes, a tech will mess with something unexpected, so you never look there...
Click to expand...

I trust most shops and dealerships about as far I could throw their employees, but sometimes stuff just breaks and isn't related to service done at all. Yeah, if the issue is directly related to something they were fixing it could've certainly been caused by them. If you took it in for a tire rotation and your engine throws a rod, probably not though.
 
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jeepguy03 said:
I trust most shops and dealerships about as far I could throw their employees, but sometimes stuff just breaks and isn't related to service done at all. Yeah, if the issue is directly related to something they were fixing it could've certainly been caused by them. If you took it in for a tire rotation and your engine throws a rod, probably not though.
Click to expand...

Perhaps I wasn't as clear as I could have been. Although I don't believe in coincidences, that's not an absolute. As I pointed out in my post, I looked at the work done to see if any of it could be related to the new issue. Obviously, if you take your car in for a tire rotation, and the engine throws a rod, it would be very hard to connect those two (unless a jackstand slipped off the frame during tire rotation and broke something to cause a catastrophic oil leak).

However, OP took it in and had the transmission mount replaced and then experienced vibration. Those two could certainly be related, since the transmission mount is a vibration damper. However, it came to light afterwards that he had hit a curb prior to the service. At that point, I backed off the "no coincidences" theory because another unrelated event that could be related to the issue popped into the thread.

This post is not made with an argumentative bent. I'm agreeing with you. Sometimes things just break. I just urge caution when performing a root cause investigation. Don't disregard the fact that service was just performed. Start there first, then look elsewhere. If that initial look reveals no likely connection between the service parts and the failed parts, then chalk it up to "sometimes things just break" and move on with the investigation.
 
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sab said:
Perhaps I wasn't as clear as I could have been. Although I don't believe in coincidences, that's not an absolute. As I pointed out in my post, I looked at the work done to see if any of it could be related to the new issue. Obviously, if you take your car in for a tire rotation, and the engine throws a rod, it would be very hard to connect those two (unless a jackstand slipped off the frame during tire rotation and broke something to cause a catastrophic oil leak).

However, OP took it in and had the transmission mount replaced and then experienced vibration. Those two could certainly be related, since the transmission mount is a vibration damper. However, it came to light afterwards that he had hit a curb prior to the service. At that point, I backed off the "no coincidences" theory because another unrelated event that could be related to the issue popped into the thread.

This post is not made with an argumentative bent. I'm agreeing with you. Sometimes things just break. I just urge caution when performing a root cause investigation. Don't disregard the fact that service was just performed. Start there first, then look elsewhere. If that initial look reveals no likely connection between the service parts and the failed parts, then chalk it up to "sometimes things just break" and move on with the investigation.
Click to expand...

Yeah it sucks sometimes, just part of dealing with mechanical things, especially older vehicles.
 
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jeepguy03 said:
Yeah it sucks sometimes, just part of dealing with mechanical things, especially older vehicles.
Click to expand...

100%. If your profile is correct, my daily driver rolled off the assembly line when you were in 2nd grade. But I didn't buy it until you were in middle school. :oops: I'm well-experienced at keeping old vehicles running... It used to be because I was poor and cheap. Now, its because "they don't make 'em like they used to." :(
 
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