Vibration/Rumbling of drivetrain while clutch is engaged

STEFGALL

MEMBER
1985 JEEP CJ7
117,000 MILES

I have a 1985 CJ7 and a vibration/rumbling happens when accelerating. The ujoints, ball joints, lug nuts and drive shaft are fine. At any speed the vibration goes away when letting off the accelerator or pressing the clutch.

Saturday, October 19th, 2013 AT 9:45 AM

8 Replies

HMAC300

MECHANIC
48,601 POSTS

Check engine mounts and trans mounts they may be broken also make sure your belts are tight as they can cause vibrations as well.

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Saturday, October 19th, 2013 AT 10:50 AM

STEFGALL

MEMBER
3 POSTS

Mounts and belts are good. Could it be an input shaft bearing or pilot bearing? There is no shudder when reving in neutral. When I press the clutch at any speed the shudder stops. The shudder returns when I let the clutch out.

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Saturday, October 19th, 2013 AT 10:58 AM

HMAC300

MECHANIC
48,601 POSTS

Tehn check your trans to see if there is any fluid in it if there is it's probably the trans or tcase bearings making it.

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Saturday, October 19th, 2013 AT 11:00 AM

CJ MEDEVAC

MECHANIC
11,004 POSTS

HOW DID YOU CHECK THE "U-JOINTS"????

DO YOU STILL HAVE THE STOCK 2 PIECE AXLES?

MAYBE LOOK THESE OVER?

https://www.2carpros.com/questions/jeep-cj7-1985-jeep-cj7-rear-diffential

JUNE 27, IN THIS ONE

https://www.2carpros.com/questions/1985-jeep-cj7-inconsistent-curb-idle-low-power-hi-rpms/page/5

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THE MEDIC

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Saturday, October 19th, 2013 AT 12:23 PM

CJ MEDEVAC

MECHANIC
11,004 POSTS

WELL. ARE YOU ON TO ANYTHING YET?

ANY ANSWERS TO OUR QUESTIONS?

ELABORATE ANY MORE?

WE GOT MORE SUGGESTIONS

THE MEDIC

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Thursday, November 14th, 2013 AT 9:49 PM

STEFGALL

MEMBER
3 POSTS

Hi Everyone, sorry for the late reply. The project got put on hold for a bit. To answer your questions:

I checked the u joints in the drive shaft to make sure the vibration wasn't caused by a worn or loose joint. I did this by putting the jeep in neutral and trying to move the shaft side to side to see if it had play in the joint.

My rear axles have been recently upgraded to one piece axles.

I checked the trans fluid, it was slightly under, I'm thinking this may have something to do with it and that the damage is to the bearings inside the transmission.

I'm moving next week and I will have a proper garage where I can drop the transmission and take a look. Any further input is always appreciated. Otherwise, standby till we drop the transmission. Thanks!

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Thursday, November 21st, 2013 AT 5:21 AM

HMAC300

MECHANIC
48,601 POSTS

If you see rust around the seals on theujoints they are probably bad as they have run out of grease, but I kind of think it's thetrans giving you the problem.

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Thursday, November 21st, 2013 AT 7:03 AM

CJ MEDEVAC

MECHANIC
11,004 POSTS

THIS IS HOW TO CHECK YOUR U-JOINTS

SEE 1ST 2 MY PICS.I NEED TO RE-MAKE THEM, THEY ARE HARD TO READ

LOOK AT MR. HARMONIC BALANCER---HE IS 2 RINGS WITH RUBBER SANDWICHED IN THE MIDDLE, SOMETIMES THE OUTER RING STARTS "WALKING OFF" THE INNER RING WHEN THE RUBBER GETS OLD. FINALLY, IT WILL COME ALL OF THE WAY OFF. YOU CAN SEE THE RUBBER ON MINE (PAINTED) WHEN I WAS INSTALLING A REPAIR SLEEVE ON THE SEAL SURFACE. SEE PIC 3

THERE IS A PULLEY BOLTED TO THE FRONT OF THE BALANCER. DON'T MISTAKE IT FOR THE BALANCER.I TOOK 168 PICS THROUGHOUT THE INSTALL-AGE OF MY NEW TRU DOUBLE ROLLER TIMING CHAIN SET. IN PIC 4 YOU WILL SEE THE PULLEY. PIC 6, THE PULLEY IS REMOVED LEAVING THE HARMONIC BALANCER (BEING PULLED)

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THE MEDIC

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