Driveline vibration mystery

[EMD_DRIVER]

My blue 97 developed a vibration from 40MPH to 65MPH and I'll be damned, if I can find it! I originally thought it was the carrier bearing, since the rubber in the old one was toast. Wrong... While I was doing the carrier bearing, I checked the U-joints and all three are tight. I was also told that the differential carrier bearings would cause the same type of vibration, so I changed them. No difference. Then, I got a suggestion that it could be front wheel bearings. No such luck.. The vibration is not engine RPM related. It is also there, if I'm at speed and in neutral. It also does not go away, when decelerating.

I can only think of a few possible things that it could be and would like some OB opinions...

1) I could go ahead and change the U-joints...

2) I could take the rear section of the drive shaft out and have it checked for balance.

3) Rear wheel bearings??

Please help me out here guys...

 

[MUDKICKR]

have you checked the tires?

 

[icanfixall]

Are all the tires wearing well... How old are the tires.... Radials will seperate the tread from the carcus causing bubbles on the tread. Rub your hands all the way around the tread feeling for any bulges. Tires may look fine but thats the tuff thing... Replacing a tire that has plenty of tread left doesn't mean the tire has any life left... You don't need to experiance throwing tread... That kills fenders and stuff plus... It takes weeks to get the seat fixed where you hiney pinched it trying to hold on to the rig when its in need of an exersisim.... Been there too on a tall freeway transition between freeways doing 60 in a long turn..... No place to go way up there either... When I got home I needed two John Deeres to spread my cheecks to relax....

 

[EMD_DRIVER]

have you checked the tires?

Are all the tires wearing well... How old are the tires....

Tires are in great condition and were put on new in January. I actually thought of the tires, when the vibration started. They were due for rotation anyway. I rotated them and there was no change in the vibration.

 

[maddenji]

Is the carrier bearing made in China or is it a Spicer
I put made in china on my "toy truck',Ranger, and it vibrated from 40 on up.
Changed to a spicer and the vibration went away.
Just a thought
Jim

 

[OLDBULL8]

Put the rear up on jack stands, block the front wheels. Start it up then see what you have. Just don't get near the drive shaft. Have someone rev it while looking.

That will eliminate the tires.

 

[Mutley]

I've been down that road. Had to re-balance the drive shaft. Had to keep speeds well under 30 to get home. It had spun off a weight. In fact, you might inspect it first to see if one has come off. Odds are you'll find that's the problem.

 

[apextrans]

Don't know if your truck is lifted or not but I had the same type of problem & replaced my carrier bearing as well. Turned out I needed to space the carrier bearing down about an inch to lessen the driveline angle. Soon as I did that the vibration went away.

 

[dyoung14]

Take the tires and have them balanced, check the weights on the driveshaft,

Check brakes make sure none are sticking

 

[coletrain777]

My bet is on the carrier bearing or driveshaft, but on a friends truck he had almost the same symptoms and his 6 month old tires needed to be balance again... took care of the problem. Just a thought.

 

[trackspeeder]

My blue 97 developed a vibration from 40MPH to 65MPH and I'll be damned, if I can find it! I originally thought it was the carrier bearing, since the rubber in the old one was toast. Wrong... While I was doing the carrier bearing, I checked the U-joints and all three are tight. I was also told that the differential carrier bearings would cause the same type of vibration, so I changed them. No difference. Then, I got a suggestion that it could be front wheel bearings. No such luck.. The vibration is not engine RPM related. It is also there, if I'm at speed and in neutral. It also does not go away, when decelerating.

I can only think of a few possible things that it could be and would like some OB opinions...

1) I could go ahead and change the U-joints...

2) I could take the rear section of the drive shaft out and have it checked for balance.

3) Rear wheel bearings??

Please help me out here guys...

Check #2. Sometime the weights come off the drive shaft.

 

[RLDSL]

Tires are in great condition and were put on new in January. I actually thought of the tires, when the vibration started. They were due for rotation anyway. I rotated them and there was no change in the vibration.

But did you get them balanced...and even then sometimes a tire won't show it's colours when it's coming apart inside and it'll give you the shaking of a lifetime that can feel like a wheel coming off.

 

[Diesel_brad]

My bet would be a TIGHT u-joint , not a loose one

 

[Goofyexponent]

Greasable U joints or sealed? Give them a shot of grease until it pours out of all 4 caps, then wipe it clean to keep grease off non greasable parts (exhaust, body, fuel tank)

Did a weight come off a wheel? It should be visable if one came flying off.

Is there excessive play in the transmission yoke, or did the nut back off the pinion allowing that yoke to work loose?

I would check the balance of the shaft just to be sure it's balanced. Are the yokes in phase? I know it's supposed to be master splined....but mine isn't (but it was custom built)

Are your rear drums or front rotors in need of turning/replacing? I had that problem in an F150....PITA!!!

Nothing short of pulling the hubs in search of busted parts, I am out of ideas.

 

[EMD_DRIVER]

But did you get them balanced...and even then sometimes a tire won't show it's colours when it's coming apart inside and it'll give you the shaking of a lifetime that can feel like a wheel coming off.

I didn't get them balanced, but the vibration doesn't feel like a tire. It's more like going over a rumble strip, that has the strips very very close together. I'm not sure how else to describe it...