help tracking down pesky vibration

[Peroni]

I've had a driveline vibration for a while now and am chasing my tail trying to find out what is causing it. Starts at approx 35mph and smooths out above 45. Sometimes it's constant, other times it feels more like a throbbing vibration. Worse when cold but never completely goes away when warmed up. Goes away under acceleration but comes back once cruising. You can really feel it when slowing down esp in OD w/ the converter locked. It's at its worst when coasting with a load in the bed in OD.

U joints are Precision Super Strength greaseable thru the cap style (all I could get on short notice) that are just over 3yrs old. They get a shot of Schaeffers fully syn grease every 3K.

Center bearing was replaced 16 months ago with an SKF unit and the spline was greased at the same time. The blue coating was intact on splines.

Rear end was completely rebuilt early last December including new hub bearings.

Front wheel bearings replaced in April of 2012.

Front end and steering are tight with all parts being under 18 months old.

Motor mounts and trans mount are tight as are all the drivetrain bolts.

This has been ongoing for about 2yrs now and I really want to get it sorted out. I can't feel any excessive play in anything. Could the driveshaft be out of balance? Its balance weight and weighs are still in place. All parts are clean and rust free.

 

[TyCorr]

I've had a driveline vibration for a while now and am chasing my tail trying to find out what is causing it. Starts at approx 35mph and smooths out above 45. Sometimes it's constant, other times it feels more like a throbbing vibration. Worse when cold but never completely goes away when warmed up. Goes away under acceleration but comes back once cruising. You can really feel it when slowing down esp in OD w/ the converter locked. It's at its worst when coasting with a load in the bed in OD.

U joints are Precision Super Strength greaseable thru the cap style (all I could get on short notice) that are just over 3yrs old. They get a shot of Schaeffers fully syn grease every 3K.

Center bearing was replaced 16 months ago with an SKF unit and the spline was greased at the same time. The blue coating was intact on splines.

Rear end was completely rebuilt early last December including new hub bearings.

Front wheel bearings replaced in April of 2012.

Front end and steering are tight with all parts being under 18 months old.

Motor mounts and trans mount are tight as are all the drivetrain bolts.

This has been ongoing for about 2yrs now and I really want to get it sorted out. I can't feel any excessive play in anything. Could the driveshaft be out of balance? Its balance weight and weighs are still in place. All parts are clean and rust free.

Did you ever get the two halves of the driveshaft turned 90°. They will not be balanced. They are out of phase in that scenario. Just an idea Peroni!

Could your converter be screwed up? Something loose?

 

[Peroni]

I marked everything on the drive shaft before taking it apart. 100% positive it's back the way it should be.

Converter seems fine, at least it's been doing is job.

Can't seem to find anything loose? But something obviously is somewhere?

 

[smitty4605]

I had a similar problem with my two piece driveshaft. The tubes were hourglass shaped and my u-joint caps were spinning in the yoke. I upgraded to a 5" aluminum one piece and the vibrations went away.

Did you try to rebalance your tires or get an alignment? Thats a cheap way to rule two things out.

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[NotStock]

The fact that it's temp based would lead me to look at tires/wheels. Do you have a friend with a set of tires/wheels you could swap with temporarily and see if it goes away?

 

[TyCorr]

I had a similar problem with my two piece driveshaft. The tubes were hourglass shaped and my u-joint caps were spinning in the yoke. I upgraded to a 5" aluminum one piece and the vibrations went away.

Did you try to rebalance your tires or get an alignment? Thats a cheap way to rule two things out.

Sent from my C771 using Tapatalk 2

Thats on my list! Did you just buy it or have a shop build it?

 

[7.34ever]

I've had a driveline vibration for a while now and am chasing my tail trying to find out what is causing it. Starts at approx 35mph and smooths out above 45. Sometimes it's constant, other times it feels more like a throbbing vibration. Worse when cold but never completely goes away when warmed up. Goes away under acceleration but comes back once cruising. You can really feel it when slowing down esp in OD w/ the converter locked. It's at its worst when coasting with a load in the bed in OD.

U joints are Precision Super Strength greaseable thru the cap style (all I could get on short notice) that are just over 3yrs old. They get a shot of Schaeffers fully syn grease every 3K.

Center bearing was replaced 16 months ago with an SKF unit and the spline was greased at the same time. The blue coating was intact on splines.

Rear end was completely rebuilt early last December including new hub bearings.

Front wheel bearings replaced in April of 2012.

Front end and steering are tight with all parts being under 18 months old.

Motor mounts and trans mount are tight as are all the drivetrain bolts.

This has been ongoing for about 2yrs now and I really want to get it sorted out. I can't feel any excessive play in anything. Could the driveshaft be out of balance? Its balance weight and weighs are still in place. All parts are clean and rust free.

I'm betting on a rear driveshaft u-joint.....most likely the one right on the pinion cause it takes the most abuse. The reason you don't feel it when accelerating is because it's loaded with the weight of getting your truck moving. Once cruising there isn't much load on flat ground so it can slap back and forth in there. I'd yard the rear dl out and change em all.

BTW.....the blue coating on the splines won't let you put that connection together incorrectly. It skips a tooth in one spot so you can't.

 

[mint-6oh]

The fact that it's temp based would lead me to look at tires/wheels. Do you have a friend with a set of tires/wheels you could swap with temporarily and see if it goes away?

Whs^

 

[smitty4605]

Thats on my list! Did you just buy it or have a shop build it?

I had mine built. Axle Exchange in Fairfield, Nj is who I use

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[TyCorr]

We have a "professional shop" in Ottawa,IL and they cant be trusted to.do.ujoints and get shti.balanced and reassembled corrwctly. No way Id trust them to fabricate one for me. They knocked weights off mine and put them in the cupholder!! Didnt glue, weld , or even tape.them.back on.

 

[smitty4605]

My shop builds a tough driveshaft. Eric Miller uses their driveshafts in his ultra4 rig along with every other vehicle he has. I had them in my old crawler.

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[fastersteve]

So what's the name of this shop?

Where's it at?

I also have been chasing an intermittent, cyclical vibration in my X. D/S has been balanced twice. I don't trust the local driveshaft shop to make one since they can't even balance this one.

 

[smitty4605]

Axle Exchange
Fairfield,NJ
973-808-2800
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[Peroni]

Guys thanks for all the input it's appreciated.

On the possibility it's a tire - I haven't had them balanced since they were mounted almost 2yrs ago. I did rotate them after the alignment in July. There was no change with the vibration at all. If it was the tires wouldn't there have been some change to the vibration pattern by rotating them?

Think I'm going to take a ride down to Universal Automotive in Concord and see what they think. I did notice that while the blue coating on the spline is intact, it doesn't really fit all that close into the female spline. I can move it around a bit by hand. Might just see what a beefier better designed drive shaft would cost me.