40 MPH+ Vibration

[brewsky]

Not sure where to post this, but here goes...
Bone stock 94 B4000 4x4, 5-speed, 150,000 miles

Vibration begins at 40MPH and gets worse with speed increase...push in clutch no change.
By 60 MPH whole truck shaking bad enough to rattle dashboard.
Mush worse at no load or decel, smooths out on acceleration.
Had truck checked out at Ford dealer before purchase and they said only problems were ball joints (had all 4 replaced and alignment) and rear brake drums warped.
Another shop replaced front tires and said rear brakes were fine.

Where to start?

 

[martin]

Sounds like a driveshaft issue

 

[brewsky]

Your probably right, as I just crawled under it and shook it.

Found 3/16" lateral play in the slip joint which is concealed under a rubber boot (still intact), and I can hear it clank when shake it back and forth sideways.

The u-joints joints feel tight and I couldn't detect any play at the transfer case or differential end by hand, anyway, so I guess I'm looking at a new driveshaft?

 

[legoms013]

Your probably right, as I just crawled under it and shook it.

Found 3/16" lateral play in the slip joint which is concealed under a rubber boot (still intact), and I can hear it clank when shake it back and forth sideways.

The u-joints joints feel tight and I couldn't detect any play at the transfer case or differential end by hand, anyway, so I guess I'm looking at a new driveshaft?

No, just a new carrier bearing bushing and if that fixes it you are golden!

 

[brewsky]

No, just a new carrier bearing bushing and if that fixes it you are golden!

Don't think I have one....there is nothing between the transfer case and rear diff except the u-joints (double front and single rear) and a rubber boot which I assume covers a slip joint?

 

[legoms013]

Don't think I have one....there is nothing between the transfer case and rear diff except the u-joints (double front and single rear) and a rubber boot which I assume covers a slip joint?

Is your truck a single cab or super-cab? Super cab will have a 2 piece drive line with a carrier bearing, single cab won't.

 

[brewsky]

It's a single cab.....

 

[AgPete139]

I would have guess the carrier bearing as well. Are your wheels out of balance?

Do you feel it more in your steering wheel, or your seat? Do you think it's originating form the from suspension/brakes or the rear?

If clutch is in, it's not motor or tranny/t-case.

 

[heptofite]

could be the tailshaft bushing in the transmission, i have a truck with a failed bushing and it does exactly what you describe.

 

[brewsky]

The whole truck vibrates, but it almost goes away when I put a load on the engine.

The slip joint definitely has too much play, as I can see, feel and hear it when moving it sideways. So the splines have to be worn.

Advance has a driveshaft assembly for $232 which includes joints on both ends....

Is there a better solution?

 

[AgPete139]

People are going to suggest junkyards, IF you can find the part.

 

[brewsky]

Well, looks like it is used, aftermarket, or nothing as it is no longer available from Ford.

Advance sells a Fenco brand...anyone heard of it?

 

[heptofite]

eh, isn't the driveshaft the same even on the 2010s? certainly ford still makes the driveshaft for the 2010s

 

[brewsky]

Don't think so...I don't think single cab is available in 4x4 anymore

 

[brewsky]

Relpaced the driveshaft and the vibration is gone......smooth as a baby's butt now

The u-joints joints were still tight but the slop in the spline joint was obviously the problem.