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

Diagnosing vibration help please
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=1&t=85798		 Page 1 of 1
Author:  Mudduck [ Sun Dec 18, 2016 11:34 am ]
Post subject:  Diagnosing vibration help please
Hey guys, I've got a vibration that just showed up on a 2002 Liberty Sport that I need some help figureing out the cause.

192,000 miles, OME spring lift, Moab wheels, 265/70/16 Goodyear duratracs.
I've just recently had some work done, and will give you a quick recent repair list, in case it gives you some needed info to diagnose this.

Within the last week or so......
Changed left side cv axle, right side cv axle, intermediate shaft and added a clevis lift.

Everything was good for a few days, then my starter went out.
Took it back to the shop to get the starter changed, and while it was in there, replace the front pinion seal, and rotate tires.

When I got it back, it has a pretty good vibration that starts at approx 40 mph, vibrates thru 50-55 mph, clears up a little, but is still noticeable.
Probably the worst at 45 mph.
Vibration is kinda like the a washboard dirt road vibration, but not that drastic.
If you stay at that speed, it will make a droning sound.

Assumed it was a tire out of balance, although it drove good before the rotation.
Went back and balanced all four tires, but the vibration is still there.

Came home and pulled out the front driveshaft, and the vibration is gone while driving without the front driveshaft.

Any ideas?????
Please let it be something simple.
Within the last 3000 miles, I've also rebuilt the heads, and replaced the radiator.

Thanks for your help.
Author:  WWDiesel [ Sun Dec 18, 2016 11:55 am ]
Post subject:  Re: Diagnosing vibration help please
Are the front driveshaft CV joints in good shape? Boots ok, no signs of grease leaking out of joints, extra play or slop in either of the joints, etc...
Author:  Mudduck [ Sun Dec 18, 2016 12:43 pm ]
Post subject:  Re: Diagnosing vibration help please
I just went out to doublecheck, and everything looks good.
I replaced the cv head on the rear of the front driveshaft less than a year ago.
They both seem tight and boots are all good, no grease leaking, etc.
The balance weights are still on the driveshaft, also.
Seems to me the only variable is the repair of the pinion seal, since there was no vibration before that repair.
Could something have been done during that repair to cause a vibration?
I have no experience with that at all.
Something too loose, or too tight? Something not lined up correctly?
If the vibration were in the front differential somehow, would removing the front driveshaft eliminate the vibration?
Or does the vibration going away when removing the shaft, eliminate everything but the shaft itself?
Author:  WWDiesel [ Sun Dec 18, 2016 1:55 pm ]
Post subject:  Re: Diagnosing vibration help please
Once you remove the front driveshaft, everything in the front axle is still rotating, only thing not rotating is the removed driveshaft!
Have you felt of the pinion shaft with the driveshaft removed? Should be NO play, it should be good and tight. NO up and down or side to side feelable movement!

Replacing the pinion seal only involves removing the driveshaft and the pinion yoke, nothing else. Without disassembly of the whole front axle, it does involve tightening the yoke back to the required torque to achieve the correct rotational preload on the pinion bearings. If the yoke nut was overtightened or under tightened, it could cause vibration problems!
You really have to be careful when you work on pinions.... :roll:
Author:  Mudduck [ Sun Dec 18, 2016 3:13 pm ]
Post subject:  Re: Diagnosing vibration help please
I will check for loose play in the pinion shaft and report back.
So, if it were something with the front differential, pinion, etc, I would still feel the vibration with the front driveshaft removed?
I guess it's a good point, all I removed is the driveshaft.
I realize everything in the front axle is still turning, I guess I just didn't know if removing the front driveshaft would eliminate/minimize the connection between the differential and the rest of the drivetrain, thereby eliminating the vibration.
Author:  JeepinJarhead03 [ Sun Dec 18, 2016 5:46 pm ]
Post subject:  Re: Diagnosing vibration help please
statistically, diagnosis wise, if the vibration goes away with the driveshaft removed, whether its a front or rear driveshaft, then the imbalance is somewhere on that driveshaft

mud, bad cv/joint, physical loss (loss of a balancing weight) or there was some sort of imbalance in how it was mounted / loose / not oriented the same way that it originally came off
Page 1 of 1 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/