De-acceleration vibration
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Freshman User
Joined: Feb 2003
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From: Fort Worth, TX
De-acceleration vibration
I have a 1994 Ford F-150 and here lately ive developed a shaking when de-accelerating. First it was in the higher speed on the highway and now it happens almost all the time, but at lower speeds it is not a noticable. Any ideas?
Thanks
Thanks
Hotshot
Joined: Sep 2001
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If it happens during braking its probably your front brake rotors. If happens when you just let off the throttle, my first guess would be U-joints or possibly the rear end. It could be anything on the driveline though.
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Freshman User
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From: Fort Worth, TX
How will i know if its the UJoints? Now it happens mostly at highway speeds. If im cruising at 65 there is a vibration, but the vibration goes away at 75. But if i let off the gas while at those speeds, i get a vibration, but after like 2-3 seconds it goes away and i can continue to deaccel without a problem. But once i touch the gas the vibration comes right back, and if i let off again i feel it for a few seconds and then it goes away.
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I had this same thing happen on one of my "non-ford" trucks. Turned out to be the U-joints. Get up under your truck and grab hold of them with both hands and start pushing up and down. If you get any kind of movement at the joint, it is time to replace. I will say this, however, you want "always" have any movement in the joint and it may still be bad. One thing I would do before replacing the u-joints is to get your truck up to a speed above that at which you feel the vibration (75 mph). Then throw the truck into neutral and let it coast back down through the speed at which you felt the vibration (65). If you don't feel it then, then you have isolated the vibration to the joints because the driveshaft isn't turning when in neutral. This works better if you have a tach to monitor rather than the speedo. HTH
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Freshman User
Joined: Feb 2003
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From: Fort Worth, TX
THanks for all the info ill check it out, when driving and i put it in nuetral it vibrates but i never let it coast down. BUt ill check the ujoints, thanks for all the info.
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Hotshot
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"The driveshaft isn't turning when in neutral."
The drive shaft does turn even when in neutral. No transmission selection will stop the driveshaft from turning.
The drive shaft does turn even when in neutral. No transmission selection will stop the driveshaft from turning.
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Originally Posted by ForTiLLiaN
THanks for all the info ill check it out, when driving and i put it in nuetral it vibrates but i never let it coast down. BUt ill check the ujoints, thanks for all the info.
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Originally Posted by crawdad
If it is still vibrating when you shift into neutral, it is not your driveshaft. The driveshaft doesn't rotate in neutral. I would check my wheels and tires next. Possibly out of balance, out of round, etc. You may have thrown a wheel weight at some point.
Last edited by 02FordFx4; Jan 30, 2006 at 07:31 PM.
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From: Florida
Loose U-Bolt's, or worn out spring bushing's, will also cause it. When you are accelerating the rear end has pressure on it, when you let off it will move around/back an forth. Just something else to check.
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Originally Posted by 02FordFx4
As texasguy said the driveshaft is going to continue to turn when the transmission is in nuetral. As long as the rear wheels are spinning, the driveshaft will continue to spin. The only thing shifting to neutral will do, is tell you if it is a transmission vibration. It is most likely the U-joints, my non ford truck used to do the same exact thing except when you let off the gas it would make a nice "clunk" noise.
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Joined: May 2003
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From: Raleigh
I had a vibration from my rear end. Sounded like yours - only there at about 65mph. I replaced my U-joints and got nothing. While I was down there I saw a little leak in from the pinion seal. Decided to replace it and noticed that my pinion flange was, well, on the loose side. I wasn't happy to find that out, but I did drive it from New Mexico to North Carolina and it didn't really seem to care.
