Hi Fellas, Truck has a noticable vibration at 55mph-5 gear. Felt through the body, but not in the steering. Not as noticable in the lower gears at the same rpm. Rear end is new. U joints are good. No brake drag. Had all wheels re-balanced. Getrag is overfilled. Any ideas on this vib problem would be appreciated... It's irritating the #*#! out of me... ... ... . thanks
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driveline vibration???
- Thread starter GGott
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Is it RPM or speed specific? Try it in 4th @55 (dont worry, if I can do 65 with 4. 10s, you'll be just fine with your 3. 54s @ 55). If it still does it, it could be your driveshaft out of line- warped. If it isnt speed specific, it could be the transmission itself paking up to head south on ya at the most inopportune mooment imaginable. 
Daniel
Daniel
U joints are good.
Do they just look good or do you KNOW they are good. Had a problem with a joint once that was not showing any loosness but was freezing up on half the cross. If the shake is in the drive line it will have a frequency that is speed specific. New rear end? Did they get the back joint in properly. Mud on a rear wheel? Bent wheel on the back?
1stgen4evr
James
Do they just look good or do you KNOW they are good. Had a problem with a joint once that was not showing any loosness but was freezing up on half the cross. If the shake is in the drive line it will have a frequency that is speed specific. New rear end? Did they get the back joint in properly. Mud on a rear wheel? Bent wheel on the back?
1stgen4evr
James
I have had tires that vibrated at a certain speed like your speaking about.
Just because there balanced doesn't mean there round ether. Try dropping your tire presure 5 pounds on the back to allow the sidewalls to flex a little more and see what happens.
Also if you have the means jack it up and run it so you can see if it is round.
I bought brand new tires at a new tires store and they had this fancy machine. On the way home my truck was vibrating like you said.
The next weekend I went back and when I told the guy he didn't let me finish before telling me to pull it in the first bay. They had problems from lots of folks because there new machine was set up wrong.
Got it redone and everything has been fine since.
Good Luck@
Just because there balanced doesn't mean there round ether. Try dropping your tire presure 5 pounds on the back to allow the sidewalls to flex a little more and see what happens.
Also if you have the means jack it up and run it so you can see if it is round.
I bought brand new tires at a new tires store and they had this fancy machine. On the way home my truck was vibrating like you said.
The next weekend I went back and when I told the guy he didn't let me finish before telling me to pull it in the first bay. They had problems from lots of folks because there new machine was set up wrong.
Got it redone and everything has been fine since.
Good Luck@
Couple tips...
You can have tires that can be out of balance warm and not show it cold. Try getting a tire balance and show up with warm (20 miles or more driven at 60mph) tires.
Other tip... mark the location of the rear yoke to driveshaft. Take the driveshaft off of the rear end yoke and rotate one or the other 180* and reassemble. DON'T let a ujoint cap fall off. If the rear end is new (overhauled or swapped?), someone may have gotten something out of phase. You can try this and see if it helps. Also check your ujoint for play and motion while it is off the yoke. Grease the ujoints as long as you are under there getting dirty.
You can also set the rear end up on jack stands (securely block the front wheels) and start the truck. Put it in gear and check the rear wheels for wobble standing back about 10' or so. You have to watch out for flying rocks or gravel if you have some in your tire tread. This trick works best with two people, but with no drag the truck usually maintains 35-40 mph by itself. Maybe more if you put it in fifth. Usually you can get it up to speed and lean out or step out to watch the tires. You can also take a peek at the driveshaft while it is rotating and see if it wobbles. Be EXTREMELY careful to stay out away from the tires and driveshaft while all this is turning.
While all this is turning, watch the sides of the rims for runout. Watch the top or bottom of the tread for runout as well. Wobbly rims will be apparent. Out of round tires will be apparent too, but only if the tires are warm. They will be a little flat-spotted if cold. Also take a look for broken belts or one side of tire that has a bubble or high spot in tread.
Good luck!
You can have tires that can be out of balance warm and not show it cold. Try getting a tire balance and show up with warm (20 miles or more driven at 60mph) tires.
Other tip... mark the location of the rear yoke to driveshaft. Take the driveshaft off of the rear end yoke and rotate one or the other 180* and reassemble. DON'T let a ujoint cap fall off. If the rear end is new (overhauled or swapped?), someone may have gotten something out of phase. You can try this and see if it helps. Also check your ujoint for play and motion while it is off the yoke. Grease the ujoints as long as you are under there getting dirty.
You can also set the rear end up on jack stands (securely block the front wheels) and start the truck. Put it in gear and check the rear wheels for wobble standing back about 10' or so. You have to watch out for flying rocks or gravel if you have some in your tire tread. This trick works best with two people, but with no drag the truck usually maintains 35-40 mph by itself. Maybe more if you put it in fifth. Usually you can get it up to speed and lean out or step out to watch the tires. You can also take a peek at the driveshaft while it is rotating and see if it wobbles. Be EXTREMELY careful to stay out away from the tires and driveshaft while all this is turning.
While all this is turning, watch the sides of the rims for runout. Watch the top or bottom of the tread for runout as well. Wobbly rims will be apparent. Out of round tires will be apparent too, but only if the tires are warm. They will be a little flat-spotted if cold. Also take a look for broken belts or one side of tire that has a bubble or high spot in tread.
Good luck!
I've had a bent stock steel rim give me a little vibration, and I had a junkyard replacement rim give a slight vibration because the chamfers on the holes were worn too much and the lugs didn't seat it against the hub.
Jack up the truck, spin the tires and see if they look like they are running true.
That's been suggested already, but it's an easy check.
Good luck.
Jay
Jack up the truck, spin the tires and see if they look like they are running true.
That's been suggested already, but it's an easy check.
Good luck.
Jay
I also agree about the phase of the shaft but I think it only would need to be turned 90 degrees, not 180. If you moved it 180, it would still be out of phase if it is now.
If it is a bad joint, try letting off just a slight amount on the fuel peddle to get the load off the joint. This is when they will vibrate the worst if there is a bad joint. Don't let off all the way as this will load it the other direction.
The joints can still feel tight when checked by hand but can have bad needle bearings. I had mine replaced last year due to vibration and there was a bad joint. Couldn't feel any slop in the joint but it had to be bad and was.
If it is a bad joint, try letting off just a slight amount on the fuel peddle to get the load off the joint. This is when they will vibrate the worst if there is a bad joint. Don't let off all the way as this will load it the other direction.
The joints can still feel tight when checked by hand but can have bad needle bearings. I had mine replaced last year due to vibration and there was a bad joint. Couldn't feel any slop in the joint but it had to be bad and was.
That's correct... rotating 180 will not change the phasing.
An out-of-phase condition could manifest itself as vibration... that would be not noticable at low speeds and noticable at highway speeds.
But... .
I doubt very seriously if the driveline u joints are out of phase on a production driveshaft.
Something that will put an oem designed driveshaft out of phase is lifting the suspension... that will change the u-joint angles and hence there will be a phasing error.
I don't have the knowledge to know how much phasing error there can be before it becomes noticable... .
In steering we use 10% as the magic number... . but that's in "perceivable steering effort" and a slow speed application.
Rotating 180 might however might eliminate/minimize runout of the system... ... . or make it worse. Might be worth trying.
Jay
Here I go again....
So are you all saying that the yoke on the transmission and the yoke on the diff need to be 90 off from each other? Does that really make a difference? I never paid attention to it before.
So are you all saying that the yoke on the transmission and the yoke on the diff need to be 90 off from each other? Does that really make a difference? I never paid attention to it before.
90 degrees off
Yes it makes a difference. The drive line is off by 90 degrees on purpose. It can not be otherwise unless the slip joint in the middle is assembled wrong. I have changed several joints but I don't pull the slip joint apart so I can not say if it has a master spline. If it doesn't, then the shaft(slip joint) can be assembled so that the transmission and diff yoke are not 'factory' at 90 degrees off. Note that the crosses are all lined up. There are applications on Timber Jack skidders where the crosses are set up out of phase by one spline at the slip joint. (Anti vibration related)
I just checked three different trucks and they all are 90 degrees off. These are two piece drive lines and I don't know if any of the first gens have a single piece driveline. I could not say what those require.
GGott states that the rear end is new. Was the rear shaft out and was it reinstalled properly at the slip joint?
James
Yes it makes a difference. The drive line is off by 90 degrees on purpose. It can not be otherwise unless the slip joint in the middle is assembled wrong. I have changed several joints but I don't pull the slip joint apart so I can not say if it has a master spline. If it doesn't, then the shaft(slip joint) can be assembled so that the transmission and diff yoke are not 'factory' at 90 degrees off. Note that the crosses are all lined up. There are applications on Timber Jack skidders where the crosses are set up out of phase by one spline at the slip joint. (Anti vibration related)
I just checked three different trucks and they all are 90 degrees off. These are two piece drive lines and I don't know if any of the first gens have a single piece driveline. I could not say what those require.
GGott states that the rear end is new. Was the rear shaft out and was it reinstalled properly at the slip joint?
James
Tugboat,
To answer your question, I'm not sure where the phasinh should be... but wherever it is it must not be changed.
James says they are at 90 degrees... I'm sure that's correct, but I haven't paid attention... when the time comes to rebuild the u joints, I WILL pay attention.
MOST of our steering shaft u joints are at some angle... not 180, not 90, but then again we normally have large operating angles and in more than one direction, and not always equal.
***Warning... the below is somewhat geeky***
What happens is if you were to look at the velocity curves generated by the two cross trunions, they form a sine wave, changing at 90 deg. To optimize the system, the phasing on each end needs to be rotated such that the curves are as close to opposite each other as possible. If they can be truely opposite, then the velocity error will be zero and each 90 deg quadrant of the rotation will cancell out the eror on the opposite end of the shaft... .
The steeper the operating angles get, the more difficult it is to have the ends be opposite and cancel out to zero. If the two angles are different, that compounds the problem.
In this case the system must be 'optimized' to achieve as little error as possible.
We have proprietary software that calculates these angles.
Sorry for the lengthy and geeky post, but I wanted to give enough info for some of you guys to understand. This is only a 10,000 ft view.
If you are a glutton and feel you want more info please contact me privately at the e-address in my signature. But if you do, I'll report it to the Pastor, who will likely acces a 10 rwhp penalty.
Jay
To answer your question, I'm not sure where the phasinh should be... but wherever it is it must not be changed.
James says they are at 90 degrees... I'm sure that's correct, but I haven't paid attention... when the time comes to rebuild the u joints, I WILL pay attention.
MOST of our steering shaft u joints are at some angle... not 180, not 90, but then again we normally have large operating angles and in more than one direction, and not always equal.
***Warning... the below is somewhat geeky***
What happens is if you were to look at the velocity curves generated by the two cross trunions, they form a sine wave, changing at 90 deg. To optimize the system, the phasing on each end needs to be rotated such that the curves are as close to opposite each other as possible. If they can be truely opposite, then the velocity error will be zero and each 90 deg quadrant of the rotation will cancell out the eror on the opposite end of the shaft... .
The steeper the operating angles get, the more difficult it is to have the ends be opposite and cancel out to zero. If the two angles are different, that compounds the problem.
In this case the system must be 'optimized' to achieve as little error as possible.
We have proprietary software that calculates these angles.
Sorry for the lengthy and geeky post, but I wanted to give enough info for some of you guys to understand. This is only a 10,000 ft view.
If you are a glutton and feel you want more info please contact me privately at the e-address in my signature. But if you do, I'll report it to the Pastor, who will likely acces a 10 rwhp penalty.
Jay
***Warning... the below is somewhat geeky***
What happens is if you were to look at the velocity curves generated by the two cross trunions, they form a sine wave, changing at 90 deg. To optimize the system, the phasing on each end needs to be rotated such that the curves are as close to opposite each other as possible. If they can be truely opposite, then the velocity error will be zero and each 90 deg quadrant of the rotation will cancell out the eror on the opposite end of the shaft... .
The steeper the operating angles get, the more difficult it is to have the ends be opposite and cancel out to zero. If the two angles are different, that compounds the problem.
In this case the system must be 'optimized' to achieve as little error as possible.
We have proprietary software that calculates these angles.
:{
What happens is if you were to look at the velocity curves generated by the two cross trunions, they form a sine wave, changing at 90 deg. To optimize the system, the phasing on each end needs to be rotated such that the curves are as close to opposite each other as possible. If they can be truely opposite, then the velocity error will be zero and each 90 deg quadrant of the rotation will cancell out the eror on the opposite end of the shaft... .
The steeper the operating angles get, the more difficult it is to have the ends be opposite and cancel out to zero. If the two angles are different, that compounds the problem.
In this case the system must be 'optimized' to achieve as little error as possible.
We have proprietary software that calculates these angles.
:{Maybe I shouldn't have slipped in the "phase word" but it is important. It was actually a two part answer. You can phase in the front and rear driveshafts, and all the ujoints too (they are supposed to be in a certain way).
In my reference to the rear ujoint/yoke assembly, that is more of a balanced issue. Just like the tire shops do if a tire takes a high amount of weight. They air out, break the bead, and spin the tire 180*, then rebalance to see if it takes less weight.
The 180* reference to the rear yoke is all you can spin the driveshaft on the yoke. There are only two mounting points on any yoke. You can't spin the whole driveshaft 90*. You can just spin the center splined section of a two piece shaft . You are always supposed to mark the relation of driveshafts and their respective mounts on the yokes whenever doing a removal of driveshaft. The driveshaft should be balanced, but the yokes, transfer case shafts and internals, and the rear end axle shafts and internals are not. Removing one end from the yoke and rotating the driveshaft 180* over can neutral out or lessen an out of balance between the two assemblies. Rotating the driveshaft 180* will have no effect upon the phase of the driveshaft, as the yokes on either end will be in the same relative position to each other after the flip. The t-case output and rear pinion yoke should be on the same position to the driveshaft (parallel and not perpendicular), unless the driveshaft is a slip yoke design on the trans or t-case. Rotating the middle of a two piece driveshaft will affect its phase.
Due to balance issues, someone (owners or factory people) may have rotated the assembly. This is why it is important to note the phasing of the driveshaft if disassembled and the repective locations upon the yokes of the rear end and t-case. Just for kicks I went out and looked to see how many vehicles just happened to be "in phase". I have an 84 W150 that is in phase, a 2003 Toyota Tundra in phase, my 90 D350 is out of phase (has vibration issues), and a 90 Nissan that is out of phase (and also has vibration issues). Double-checking with some service manuals, the front ujoint and the rear ujoint are supposed to be assembled in the same plane exactly parallel to each other on the shaft. This is the way they are supposed to be when balanced as an assembly at the factory.
If you have vibration troubles, check for phasing of shafts. A simple rotation on the rear driveshaft yoke may also help. It is hard to tell how much tinkering our trucks have had.
Explaination clear as mud???
In my reference to the rear ujoint/yoke assembly, that is more of a balanced issue. Just like the tire shops do if a tire takes a high amount of weight. They air out, break the bead, and spin the tire 180*, then rebalance to see if it takes less weight.
The 180* reference to the rear yoke is all you can spin the driveshaft on the yoke. There are only two mounting points on any yoke. You can't spin the whole driveshaft 90*. You can just spin the center splined section of a two piece shaft . You are always supposed to mark the relation of driveshafts and their respective mounts on the yokes whenever doing a removal of driveshaft. The driveshaft should be balanced, but the yokes, transfer case shafts and internals, and the rear end axle shafts and internals are not. Removing one end from the yoke and rotating the driveshaft 180* over can neutral out or lessen an out of balance between the two assemblies. Rotating the driveshaft 180* will have no effect upon the phase of the driveshaft, as the yokes on either end will be in the same relative position to each other after the flip. The t-case output and rear pinion yoke should be on the same position to the driveshaft (parallel and not perpendicular), unless the driveshaft is a slip yoke design on the trans or t-case. Rotating the middle of a two piece driveshaft will affect its phase.
Due to balance issues, someone (owners or factory people) may have rotated the assembly. This is why it is important to note the phasing of the driveshaft if disassembled and the repective locations upon the yokes of the rear end and t-case. Just for kicks I went out and looked to see how many vehicles just happened to be "in phase". I have an 84 W150 that is in phase, a 2003 Toyota Tundra in phase, my 90 D350 is out of phase (has vibration issues), and a 90 Nissan that is out of phase (and also has vibration issues). Double-checking with some service manuals, the front ujoint and the rear ujoint are supposed to be assembled in the same plane exactly parallel to each other on the shaft. This is the way they are supposed to be when balanced as an assembly at the factory.
If you have vibration troubles, check for phasing of shafts. A simple rotation on the rear driveshaft yoke may also help. It is hard to tell how much tinkering our trucks have had.
Explaination clear as mud???
the system must be 'optimized' to achieve as little error as possible.
And more geekie stuff. I mentioned that TimberJack skidders (ours were 235 prehaulers) had the drive line on the rear shaft out of phase. The story in the field was that some dimwit with no particular expertise assembled the shaft wrong and his skidder didn't have any vibrations when in a steep turn as all others did. More likely, the factory had used some propriotary methods to find the correct (best) application.
I have worked with drive lines and built some in the shop. Experimented with out of phase operation trying to configure (optimize) an application. I actually do understand the things mentioned by Jay and Midwest. BUT, that info and 50 cents will get you a cup of coffee where they sell cheap coffee. Be sure to look at and mark your shaft before taking it down. If you do a serious skyjacking, put a block under the centermount bearing to lessen the crowding on the joints.
Are all first gens the same from the factory? I don't have the slightest idea. They do build them on Monday and Friday and I have heard of a thing called a lemon.
Going back to Ggotts original question, if the truck has 'picked up' this vibration, and didn't come with the new rear end work, then I would expect to find the problem in a joint. New work related? I remember an occassion when a needle was down in the cap causing the drive line to be off center.
PM for more detail. I will forward to Jay.
1stgen4evr
James
And more geekie stuff. I mentioned that TimberJack skidders (ours were 235 prehaulers) had the drive line on the rear shaft out of phase. The story in the field was that some dimwit with no particular expertise assembled the shaft wrong and his skidder didn't have any vibrations when in a steep turn as all others did. More likely, the factory had used some propriotary methods to find the correct (best) application.
I have worked with drive lines and built some in the shop. Experimented with out of phase operation trying to configure (optimize) an application. I actually do understand the things mentioned by Jay and Midwest. BUT, that info and 50 cents will get you a cup of coffee where they sell cheap coffee. Be sure to look at and mark your shaft before taking it down. If you do a serious skyjacking, put a block under the centermount bearing to lessen the crowding on the joints.
Are all first gens the same from the factory? I don't have the slightest idea. They do build them on Monday and Friday and I have heard of a thing called a lemon.
Going back to Ggotts original question, if the truck has 'picked up' this vibration, and didn't come with the new rear end work, then I would expect to find the problem in a joint. New work related? I remember an occassion when a needle was down in the cap causing the drive line to be off center.
PM for more detail. I will forward to Jay.
1stgen4evr
James
Check your Clutch/Trans... . I had the exact same problem... then the Getrag gagged and grenaded... ... $2200. 00 later (rebuilt unit and new clutch) and all of the vibration disappeared... not certain if it was the transmission or clutch, but I would bet on the clutch... . I had the driveshaft balanced and indexed... U joints replaced, tires rotated... et al... . the clutch and transmission job provided the fix.
I think that I would pull the rear driveshaft off, check the driveshaft thoughly as well as the yokes on the rearend and transmission. Then I would lock in the front hubs and run the truck down the road with the rear drive shaft off and see if you still have a vibration.
I have had two vibrations one turned out to be the yoke on the transmission output shaft,(the nut had backed off). The other vibration happened when under a load in fifth gear only, It turned out to be a clamp on the exhaust pipe touching the frame when the engine torqued under load. That was just a matter of rotating the clamp so the threaded ends pointed the other way.
Mark
I have had two vibrations one turned out to be the yoke on the transmission output shaft,(the nut had backed off). The other vibration happened when under a load in fifth gear only, It turned out to be a clamp on the exhaust pipe touching the frame when the engine torqued under load. That was just a matter of rotating the clamp so the threaded ends pointed the other way.
Mark
Hi again fellas. . Have done some of your suggestions concerning drive line vibration... 1) Equalize and lower tire pressure 5lbs to 50lbs and re-torque wheel lugs to pattern and specified torque. 2) Re-torque rear spring U bolts... they were under torqued. . 3) Re-placed U joints on rear driveshaft. . this reduced the vibration about 30%... The driveshaft was installed the way that it came out after the rear diff swap. The yolks on the diff and the t-case are not 90 degrees apart, but are not quite parrellel either..... Still has vibration that seems to be worse at 55 mph in 5 gear and goes away around 65 mph... ... . Tried it in 4th as suggested by Daniel, not as noticable... ... Any and all suggestions/ideas appreciated Thanks
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