Vibration
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8th Gear
Joined: Mar 2011
Posts: 8
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Vibration
Hey Guys. New to the forum. Not sure if I should post this here or in the drivetrain section. Anyway, here goes:
I have an '85 F250 4x4 4 speed 6.9L Diesel with 190K miles on it. Yesterday while driving on the freeway I noticed a vibration which I believe is coming from the driveline somewhere. Everything is fine all the way through 4th gear, however when I approach around 55mph I get this vibration. It seems to vibrate more when I'm on the gas and let off a little when I'm off the gas.
The U-Joints are tight and both weights are still attached to the driveshaft.
Any ideas?
Thanks for any help. I need to get this ironed out.
I have an '85 F250 4x4 4 speed 6.9L Diesel with 190K miles on it. Yesterday while driving on the freeway I noticed a vibration which I believe is coming from the driveline somewhere. Everything is fine all the way through 4th gear, however when I approach around 55mph I get this vibration. It seems to vibrate more when I'm on the gas and let off a little when I'm off the gas.
The U-Joints are tight and both weights are still attached to the driveshaft.
Any ideas?
Thanks for any help. I need to get this ironed out.
Moderator
Joined: Jan 2001
Posts: 56,965
Likes: 2,725
From: Virginia
Sounds like the bushing in the transfer case is worn where the driveshaft slips in, or your large nut on the differential yoke has come loose. To check it, block the wheels and put the transfer case in neutral to get all the strain off the shaft. Then get toward the front and pull up and down on the shaft. If it has a lot of play where it goes into the transfer case, and you also have some oil leaking there, chances are the bushing is worn too much. Also go to the rear of the shaft at the differential and do the same thing, try to move the shaft up and down, back and forth. If there is play there, I would take the driveshaft out and check the large nut in the middle of the diff yoke and make sure it's tight. If it's tight, you could also have a bearing going out in the diff.
Senior User
Joined: Feb 2011
Posts: 126
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From: Sequim, WA.
To MaxStar...I agree with Franklin2...From what you described it sounds like you have that old Ford problem called "resonant driveshaft throwout" in simple terms...a vibration from a worn bushing on the transfer case yoke assy....Do like Franklin2 says and you will prolly find it...
A little story...I have had this happen twice...1st time...bushing...2nd time I thought it was the bushing again....I found a big stone that got itself jammed in between the u-joint and the yolk nut...it was just rattling around in there until the driveshaft was spinning. It would have prolly made it's way out in time...but could have jerked something up...LOL
Anyway...good luck man...
Pete
A little story...I have had this happen twice...1st time...bushing...2nd time I thought it was the bushing again....I found a big stone that got itself jammed in between the u-joint and the yolk nut...it was just rattling around in there until the driveshaft was spinning. It would have prolly made it's way out in time...but could have jerked something up...LOL
Anyway...good luck man...
Pete
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Joined: Nov 2007
Posts: 22,415
Likes: 92
From: Denver Metro Area, CO
Are you going to pull it and replace parts without first checking it for yourself and verifying
this is the problem?
Man, the best anybody on the Internet can do is give educated guesses to where the
problem *could* be, it is still up to you to find the problem and fix it.
Not trying to slam Franklin2 or Pete or anybody else (I think they know that), just trying to
save you the possible grief of replacing components that don't need replacing and don't fix
your problem.
this is the problem?
Man, the best anybody on the Internet can do is give educated guesses to where the
problem *could* be, it is still up to you to find the problem and fix it.
Not trying to slam Franklin2 or Pete or anybody else (I think they know that), just trying to
save you the possible grief of replacing components that don't need replacing and don't fix
your problem.
Moderator
Joined: Jan 2001
Posts: 56,965
Likes: 2,725
From: Virginia
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Thread Starter
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8th Gear
Joined: Mar 2011
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So, I pulled the shaft this morning and there she was; a sticky U-joint. Pressed in a couple of new ones and problem solved. Thanks guys for all your help.
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Joined: Mar 2008
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From: Prairieville, La
I had a similar problem last week. A hunk of iron came off a truck and hit under my truck. I started getting a slight vibration. I drove it a couple of days and noticed it vibrated a good bit at 38 mph and smoothed out at 55.
I looked up under the truck again and saw that the iron had put a slight kink in my driveshaft. I put another one in from my parts truck and all vibration went away.
I looked up under the truck again and saw that the iron had put a slight kink in my driveshaft. I put another one in from my parts truck and all vibration went away.
