93 F150 shaking at 50mph whats wrong ?

XJMUDDER · 02-08-2009, 03:58 PM

My son just got his 93 F150 on the road today he has been working on and off it for awhile now and today was the first day out but the problem he has now is that at around 50mph to almost 60 it shakes/vibrates through the who truck really bad he has new tires on the stock wheels and they seemed to balance out ok so don't think its the tires he did have to replace one u-joint in the rear driveshaft but that came out ok and the other seemed to be all right. anybody know what it might be or what he should look at ? his truck is a shortbed reg. cab, 302 auto and 4wd. thanks for any help you guys can give us !

stumpuller454 · 02-08-2009, 04:44 PM

check the tires for seperation, and probly get an alignment done, may need to increase the caster and get rid of the "shopping cart effect"

eponator · 02-08-2009, 05:17 PM

Quote:

Originally Posted by stumpuller454

check the tires for seperation, and probly get an alignment done, may need to increase the caster and get rid of the "shopping cart effect"

Exactly what he said!!

leolkfrm · 02-08-2009, 05:20 PM

check for a bent wheel, make sure he torqued the wheels on evenly, a partial caliper siezure will also do it

XJMUDDER · 02-09-2009, 08:23 AM

The tires are brand new cooper m&s tires and he said the wheels didn't look bad , tires balanced good . the tires he took off looked like they wore pretty even all the way around. this is really the first time it has been on the road since he had bought it 3 or 4 months ago.he has been tinkering on it in that time he put new brakes , a u-joint changed all the fluids etc. just went through and checked everything as this truck had been sitting around for a year to a year and a half . and yesterday was the first time he had had it on the road . he said that it started shaking around 50mph said up till about 60 he said if he let off the throttle and it downshifted it seemed to go away ? but then as i told him he would be back down below 50, the first thing i thought was a tire not balanced good but he did them his self and said they took some weight but nothing bad and wheels didn't seem bad either. could it be anything in the drivetrain ? the frontend feels good he said he would get a alingment done if thats what you guys thought but wanted to find out if it could be something else.he drove it back to work this morning so will talk with him later to see if anything has changed.Thanks for the help.

75K30 · 02-09-2009, 09:28 AM

When folks change u-joints it is possible that the driveshaft does not go back together in 'phase" and if the splines are off by just one, it can result in a vibration.
Letting off of the gas, and perhaps the downshift might also indicate and even support this.
The replacement of the u-joint and this vibration seem to have a common variable, so I would suggest that this be verified.

XJMUDDER · 02-12-2009, 06:03 PM

Quote:

Originally Posted by 75K30

When folks change u-joints it is possible that the driveshaft does not go back together in 'phase" and if the splines are off by just one, it can result in a vibration.
Letting off of the gas, and perhaps the downshift might also indicate and even support this.
The replacement of the u-joint and this vibration seem to have a common variable, so I would suggest that this be verified.

What is the fix for this if it is the u-joint ? and how will we know for sure if thats what it is will i just have to turn the shaft and then put it back in to see if its and will i need new joint . Thanks

XJMUDDER · 02-23-2009, 06:15 PM

Thought i would let you guys know it has stopped shaking by its self . he told me that after driving it a few more times it got better each time and now its stop all together. maybe it just had some rust or ? around one of the u-joints or driveshaft or something. but the bad thing is now the radiator is leaking !

leolkfrm · 02-24-2009, 01:23 PM

That's an easy fix, change it!

gmctrucks · 02-25-2009, 05:54 AM

I was thinking first that it could have been some mud or snow on the back side of the rim that can fool one real good.

02-08-2009, 03:58 PM	#1
XJMUDDER Senior Member Join Date: Nov 2008 Location: Vermont Posts: 73	93 F150 shaking at 50mph whats wrong ? My son just got his 93 F150 on the road today he has been working on and off it for awhile now and today was the first day out but the problem he has now is that at around 50mph to almost 60 it shakes/vibrates through the who truck really bad he has new tires on the stock wheels and they seemed to balance out ok so don't think its the tires he did have to replace one u-joint in the rear driveshaft but that came out ok and the other seemed to be all right. anybody know what it might be or what he should look at ? his truck is a shortbed reg. cab, 302 auto and 4wd. thanks for any help you guys can give us !

02-08-2009, 04:44 PM	#2
stumpuller454 Senior Member Join Date: Dec 2007 Location: Grande Prairie, AB Posts: 2,043	check the tires for seperation, and probly get an alignment done, may need to increase the caster and get rid of the "shopping cart effect" __________________ SUPERCHARGED 454 K2500 GMC! 450hp and 600ft/lbs http://www.youtube.com/watch?v=WJ27RJHfJKE "sailing with Captain Morgan often!"

02-08-2009, 05:20 PM	#4
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	check for a bent wheel, make sure he torqued the wheels on evenly, a partial caliper siezure will also do it __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

02-24-2009, 01:23 PM	#9
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	That's an easy fix, change it! __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

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02-09-2009, 08:23 AM	#5
XJMUDDER Senior Member Join Date: Nov 2008 Location: Vermont Posts: 73	The tires are brand new cooper m&s tires and he said the wheels didn't look bad , tires balanced good . the tires he took off looked like they wore pretty even all the way around. this is really the first time it has been on the road since he had bought it 3 or 4 months ago.he has been tinkering on it in that time he put new brakes , a u-joint changed all the fluids etc. just went through and checked everything as this truck had been sitting around for a year to a year and a half . and yesterday was the first time he had had it on the road . he said that it started shaking around 50mph said up till about 60 he said if he let off the throttle and it downshifted it seemed to go away ? but then as i told him he would be back down below 50, the first thing i thought was a tire not balanced good but he did them his self and said they took some weight but nothing bad and wheels didn't seem bad either. could it be anything in the drivetrain ? the frontend feels good he said he would get a alingment done if thats what you guys thought but wanted to find out if it could be something else.he drove it back to work this morning so will talk with him later to see if anything has changed.Thanks for the help.

02-09-2009, 09:28 AM	#6
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	When folks change u-joints it is possible that the driveshaft does not go back together in 'phase" and if the splines are off by just one, it can result in a vibration. Letting off of the gas, and perhaps the downshift might also indicate and even support this. The replacement of the u-joint and this vibration seem to have a common variable, so I would suggest that this be verified.

02-23-2009, 06:15 PM	#8
XJMUDDER Senior Member Join Date: Nov 2008 Location: Vermont Posts: 73	Thought i would let you guys know it has stopped shaking by its self . he told me that after driving it a few more times it got better each time and now its stop all together. maybe it just had some rust or ? around one of the u-joints or driveshaft or something. but the bad thing is now the radiator is leaking !

02-25-2009, 05:54 AM	#10
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,030	I was thinking first that it could have been some mud or snow on the back side of the rim that can fool one real good.

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