Humming/Slight Vibration Front End - Help! - Jeep Garage - Jeep Forum

Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WJ > Troubleshooting/Problems

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 08-15-2016, 01:03 PM
Member
 
Join Date: Nov 2015
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 444
lordgrape is on a distinguished road
Humming/Slight Vibration Front End - Help!


So, here's my issue. I have a 1999 Jeep Grand Cherokee Limited with a 4" Rough Country lift. I bought it from a friend and immediately noticed a slight vibration and a weird humming sound in the front end that I could control whether it was there or not by the gas pedal. Let off the pedal and it went away, barely touch the gas and it returns. It came and went in intensity when the suspension flexed, so when the suspension sank it mostly, if not all, went away. When the suspension rose (like on the highway and the vehicle rises when driving as the road surface fluctuates) it intensified or came back.
Brought it in and a 4x4 shop said it was the pinion bearing, so I had them change it and all the seals in the front end. Sound is still there, but the tone has changed so I do believe the pinion bearing was bad. Next they said the front driveshaft needed to be rebuilt (specifically the cardan joint) so I had that done. The sound is still there. It's a low, humming type sound you can only hear at speeds of about 45 or greater. It increases in sound the faster I go. The wheel bearings/hubs are new. I can still mostly control the sound with the gas pedal.

Could the bad pinion bearing have caused the ring and pinion gear to have changed wear pattern to the point that it's now making noise? I'm going to pull the front driveshaft and drive it and will repost to let everyone know if the sound goes away.
Any help would be great!

Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 08-15-2016, 05:17 PM
Frango100's Avatar
The beast from Brazil

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 7,329
Thanks: 17
Thanked 378 Times in 365 Posts
Rep Power: 529492
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Humming/Slight Vibration Front End - Help!

No expert on lift and related problems, but what about the angle of the prop shaft with the differential? Is the T-case lowered?That playing with the accelerator changes the sound, points to some part of the driveline which is causing it. Did you check the differential fluid for metal glinsters, which could point towards wear of one of the gears/bearings?
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
KYB Gas-a-Just shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #3  
Old 08-15-2016, 05:41 PM
Member
 
Join Date: Nov 2015
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 444
lordgrape is on a distinguished road
Re: Humming/Slight Vibration Front End - Help!

That has crossed my mind. The guy I bought the Jeep from did the lift but didn't use the transfer case drop down bolts because "what's the point of a lift if you're lowering the transfer case". I thought that may have been something that should have been done to keep the drive angle correct. Perhaps that could have caused the pinion bearing to go bad? Don't know.
As far as wear metal, the shop that had the gear apart didn't mention anything, but I could ask them how the fluid looked. That may be my next attempt at a solution - install the drop down bolts on the transfer case. Has anyone else heard of/seen front driveline humming due to driveshaft angle being off?
Reply With Quote
  #4  
Old 08-15-2016, 06:15 PM
Frango100's Avatar
The beast from Brazil

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 7,329
Thanks: 17
Thanked 378 Times in 365 Posts
Rep Power: 529492
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: Humming/Slight Vibration Front End - Help!

Too large prop shaft angle can cause noise and vibration. Attached two manual pages with the normal drive line angles.
Attached Files
File Type: pdf Prop shaft angles.pdf (276.4 KB, 4 views)
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
KYB Gas-a-Just shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #5  
Old 08-15-2016, 08:32 PM
Member
 
Join Date: Nov 2015
Posts: 12
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 444
lordgrape is on a distinguished road
Re: Humming/Slight Vibration Front End - Help!

Thanks! I guess I'll buy an Inclinometer and give it a shot! I suck at geometry so hope this goes well.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Slight clunk from front end just when coasting Sully6541 Troubleshooting/Problems 3 02-21-2015 11:06 AM
Quadra drive popping, humming front end area. hoffmanestates Troubleshooting/Problems 12 01-25-2015 06:51 PM
Bad Vibration and Humming from truck jcshemi Troubleshooting/Problems Discussion 3 11-09-2011 07:26 AM
slight vibration in front.. TheLostSaint Suspension/Brakes/Wheels/Tires 0 10-13-2011 11:58 AM
Vibration and Humming- '05 limited 70k jcshemi Grand Cherokee - WK 9 06-15-2011 03:15 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 01:06 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by FCA US LLC. Chrysler, Dodge, Jeep, Ram, Mopar and SRT are registered trademarks of FCA US LLC.