Vibration between 40MPH and 50MPH

[Coalsmoke]

I'm getting a consistent drive line related vibration between 40 and 50MPH, all other speeds are smooth, vibration can be felt in either 4th or 5th. Anyone had anything similar?

 

[JLEONARD]

What other conditions? Acceleration, deceleration, etc?? What style of tires?

Straight driving, left turn,right turn, etc?

 

[Coalsmoke]

No other discernible indicators to the symptoms, although it is amplified under load (as would be expected with a drive line vibration). I'm running nokians up front and new toyo open countrys on the back, its likely not a tire vibration, doesn't have the right oscillating feel to it. Feels like some form of transmission gear harmonic to me. Its a rough spot in the speed range and is fine when I am under or above it, which is why I'm not fully suspecting a bearing in the transmission either.

 

[JLEONARD]

Sometimes a "choppy" tire can make funny vibes. Happened on our Jetta tdi last year but only on a right turn when the tire was loaded to the outside.

Can you feel the floor above the transmission when the vibration happens? Does it transfer to the floor? Thru the shifter?

Do you feel the vibration in your feet? Butt? Hands?

Or do you just hear it?

Sorry for the 20 questions just trying to help nail it.

 

[Greenleaf]

U-Joint. Check them unloaded by turning one shaft against the other. If there is tension on them, they won't wiggle at all and you won't feel the play. It is best to block the wheel(s) and set the trans in Netural so you can turn the drive shaft (by hand) a few degrees either direction.



Jay, "choppy" would be light ripples on the surface of the water stirred up by a light wind generally under 5 knots and always on inland bodies of water... ... ... ... ... ... .

 

[JLEONARD]

Jay, "choppy" would be light ripples on the surface of the water stirred up by a light wind generally under 5 knots and always on inland bodies of water... ... ... ... ... ... .

Ok but don't start with the Pirate talk :-laf

 

[Coalsmoke]

U-Joint. Check them unloaded by turning one shaft against the other. If there is tension on them, they won't wiggle at all and you won't feel the play. It is best to block the wheel(s) and set the trans in Netural so you can turn the drive shaft (by hand) a few degrees either direction.



Jay, "choppy" would be light ripples on the surface of the water stirred up by a light wind generally under 5 knots and always on inland bodies of water... ... ... ... ... ... .

Thanks for the suggestions, but its not u-joints and the carrier bearing is ok too. Those were my initial suspects.

 

[Coalsmoke]

Sometimes a "choppy" tire can make funny vibes. Happened on our Jetta tdi last year but only on a right turn when the tire was loaded to the outside.

Can you feel the floor above the transmission when the vibration happens? Does it transfer to the floor? Thru the shifter?

Do you feel the vibration in your feet? Butt? Hands?

Or do you just hear it?

Sorry for the 20 questions just trying to help nail it.

No worries on all the questions. I feel it through the trucks body in general. It is more akin to a bearing or gear growl than a tire oscillation. I have the dash apart and am putting in gauges and will have it back together in another couple of hours. I'll take it out and see if I can locate better where I feel the vibration.

 

[NIsaacs]

Are all three u-joints in alignment? They can be bad even if there is no slack that can be felt. If they are dry and starting to bind/seize, they will cause vibration. Take the truck for about a 10 mile drive at highway speeds, then feel each u-joint, they should be cold. A warm/hot one will be bad.



Nick

 

[ChrisWilliams]

I have a similar vibration (not under load), on the 91. 5, but haven't found the cause. Changed the rear u-joint, tires, shocks, still there. Check your trans mounts and make sure something is not loose. My transfer case mount worked loose and tightening helped, but didn't solve the problem. I have a leaking rear axle seal and am thinking I might have a worn/loose axle bearing but haven't gotten that far yet. Check all the easy fixes, tires, u-joints, mounts, and look for bearing slack in the tail shaft, pinion and axles. Keep in mind, tires can cause strange vibrations. Balance and rotate to see if the vibration changes. Good luck and let us know what you find.

 

[Coalsmoke]

Sometimes a "choppy" tire can make funny vibes. Happened on our Jetta tdi last year but only on a right turn when the tire was loaded to the outside.

Can you feel the floor above the transmission when the vibration happens? Does it transfer to the floor? Thru the shifter?

Do you feel the vibration in your feet? Butt? Hands?

Or do you just hear it?

Sorry for the 20 questions just trying to help nail it.

Took it for another run late last night and its coming through the floor pans and seats.

 

[Coalsmoke]

Are all three u-joints in alignment? They can be bad even if there is no slack that can be felt. If they are dry and starting to bind/seize, they will cause vibration. Take the truck for about a 10 mile drive at highway speeds, then feel each u-joint, they should be cold. A warm/hot one will be bad.



Nick

U-Joints are brand new.

 

[Coalsmoke]

I have a similar vibration (not under load), on the 91. 5, but haven't found the cause. Changed the rear u-joint, tires, shocks, still there. Check your trans mounts and make sure something is not loose. My transfer case mount worked loose and tightening helped, but didn't solve the problem. I have a leaking rear axle seal and am thinking I might have a worn/loose axle bearing but haven't gotten that far yet. Check all the easy fixes, tires, u-joints, mounts, and look for bearing slack in the tail shaft, pinion and axles. Keep in mind, tires can cause strange vibrations. Balance and rotate to see if the vibration changes. Good luck and let us know what you find.

Thanks Chris. The rear output bearing is something I was and still am suspect of, as the seal is leaking and it may mean a bearing on the way out. With the driveshaft out there was no noticeable play in the output yoke. Also, it doesn't follow a typical bearing noise which will increase in pitch as its speed is increased. All this has me thinking about the possibilities of gear harmonics possibly being the culprit. For all I know, when the previous owner had it rebuilt, they may have replaced one gear without replacing its mate. The transmission has definitely had someone inside of it before but I'm not sure what parts were put in or when it happened.

 

[Bob Beauchaine]

I'm running Toyo H/Ts and found something interesting. I bought the front two, then the rears about 8 months later. The fronts were made in Japan - you want to guess where the rears were made - that's right - China. I had a vibration in mine but it turned out to be the rear "U" joint cap bolts on one side were loose. I ocassionally get a vibration at 60 mph but it is road specific and goes away as the road gets better.



Bob

 

[S.Morris]

Hey

Used to live in walnut grove and was partner in pacific inland powertrain about 12yrs ago...

If you don't feel it in stick , I highly doubt trans. .

Check rear diff backlash and pinion has not lost preload. check wheels and tires for balance. Make sure ujoints are all in phase. Consider having driveshaft balanced. Make sure ubolts are tight on rear springs.

Good luck.

Steve