Mechanics

VIBRATION AND WHINING/HUMMING NOISE

1999 Jeep Grand Cherokee • 141,000 miles

My jeep has developed a whining/humming noise that only occurs during acceleration. The sound is vehicle speed dependent (the sound pitch gets higher) not engine speed dependent. On flat ground it isnt too bad unless I press the gas fairly hard but when at the top of a hill where the hill starts to level off, the vibration and sound is awful. Please help me locate the source and an idea of a repair cost.
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Jesse6101
June 2, 2013.




DOES IT DO IT IN PARK AND ON THE GAS PEDAL?

THE MEDIC
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Tiny
CJ MEDEVAC
Jun 2, 2013.
Nope this sound only occurs while driving down the road. The sound becomes audible at 35-40+ mph but that could be because of the sound of the Flowmaster overpowing it at lower speeds : ). This sound only occurs while my foot is on the gas. I have checked the exhaust for anything rubbing or leaks and I found nothing. After three hours of driving above 55 mph this weekend Im preaty sure the sound and vibration is occurring somewhere in the front differential or front driveshaft or possibly transfer case or transmission. I can tell there is a little sound and vibration at the lower speeds but it's way to faint to locate below 35 mph. I do allot of driving above 55 mph in the summer as I go to Appomattox so this needs to be fixed before it drives me nuts!


Tiny
Jesse6101
Jun 2, 2013.
I did look under it again and I found a slight problem with the driveshaft. I will try uploading some pictures.


Tiny
Jesse6101
Jun 2, 2013.
I'M NOT UP ON THE CHEROKEE DRIVETRAINS OVER THE YEARS

WHAT SYSTEM DO YOU HAVE. TRANSFER CASE?

IF THIS IS PUSH BUTTON 4X4---IT MIGHT BE THAT SOMETHING DID NOT DISENGAGE. LIKE A FRONT HUB

'NUTHER POSSIBILITY

THIS IS OFTEN OVERLOOKED

. WELL THEY GET "LOOKED AT", BUT PROPER INSPECTION IS NOT DONE.I WILL REMAKE THESE PICS ONE DAY, I MADE THESE WHEN I WAS STILL SORTA "GREEN" ON THE COMPUTER, MY COLOR CHOICES LACKED. THESE ARE ON MY '46 WILLYS. YOURS ARE VERY SIMILAR

RETURN WITH A GRIN!

ARE YOU ABLE TO MAKE REPAIRS YOURSELF.I GOT MORE INFO SHOULD YOU NEED TO REPLACE THEM

THE MEDIC


Tiny
CJ MEDEVAC
Jun 2, 2013.
Nice jeep! Okay so I have checked the drive shafts for any play and I found none. I did get some pictures to show some possible causing things and I will put those on shortly. My system is a quadra trac two and it has a 247 J transfer case


Tiny
Jesse6101
Jun 2, 2013.


Tiny
Jesse6101
Jun 2, 2013.
Okay I could only get those two pictures to cooperate with me but they show my main two concerns. The first picture is showing my front driveshaft where it enters the transfer case and the rubber or whatever it is is cracked and opened almost half way around. My second concern is shown in the last picture with the rear driveshaft from the transfer case to the first u joint it almost appears to me like the driveshaft is being pulled out. I saw this at first two days ago and when I went back to look at it just now it appears as if it has come out more. These are not all of my concerns but certainly these two things appear like they could be a problem.


Tiny
Jesse6101
Jun 2, 2013.
One correction, the transfer case is a NEW PROCESS GEAR 247 J


Tiny
Jesse6101
Jun 2, 2013.
As for repairs. Yes me and my dad can do the repairs but I think if its gonna cost more than $500 then ill just sell it for somone else to do all the fun work. I've had it for only a year and I love the abilities of the quadra trac 2 system and the awesome fuel economy but with the brake problems in the past and other little things that need to be replaced, I'd rather sell the jeep and put down the extra $1000 this one is gonna need for repairs towards a nice truck.


Tiny
Jesse6101
Jun 2, 2013.
THE TRANSFER CASE/ DRIVE SHAFT MAY BE NORMAL. AS YOU HIT BUMPS, ETC, THE REAR SUSPENSION MOVES, THE DRIVE SHAFT IS PULLED IN AND OUT OF THE TRANSFER CASE ON SPLINES.

DEPENDING ON HOW YOU STOPPED IN FORWARD OR REVERSE AND HOW FAST, EVEN TERRAIN, MAY "TORQUE" THE REAR END UP OR DOWN. THIS MAY ACCOUNT FOR YOU SEEING A DIFFERENCE IN THE SHINY PORTION'S LENGTH STICKING OUT OF THE TRANSFER CASE

CAN A PASSENGER "HANG OUT" OF THE WINDOW AND LISTEN TO YOUR FRONT END?

THE DAMAGED CV BOOT IN YOUR PIC, "COULD BE" YOUR RACKET. THE BOOT KEEPS TRASH AND DIRT OUT OF THE BEARINGS. IF YOU'VE BEEN 'MUDDIN', YOU MAY HAVE ACCELERATED THE BEARING'S WEAR AND ABILITY TO WORK CORRECTLY.

A NEW CV JOINT MIGHT BE IN ORDER. WHEREVER YOU LIVE. DO YOU HAVE AN "ADVANCE AUTO PARTS" STORE NEARBY?

NEVER "SETTLE" FOR ANOTHER TROUBLE MAKER VEHICLE. IF THE WINDSHIELD WILL NOT LAY DOWN. YOU DON'T WANT IT!

THE MEDIC

I SORTA TOOK OLE TUCKER IN UNDER MY WING, HE'S IN COLLEGE, LOVES HIS JEEP, NEEDED TO LEARN HOW TO WORK ON HIS NEWLY PURCHASED JEEP. MAINLY, CATCH UP ON NEGLECTED MAINTENANCE. WE MESS W/ HIS ABOUT ONCE A WEEK

. SO, I DROPPED THE WINDSHIELD THEN I LET TUCKER DRIVE WILLY, MY '46, WHILE WE TOOK A BREAK FROM WORKING ON HIS '81 CJ 5 (HIS IS LEFT OF "WILLY" IN 1ST PIC)

. HE IS NOW HOOKED. WANTS A WILLYS TOO!

THE MEDIC


Tiny
CJ MEDEVAC
Jun 2, 2013.

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