I have a 1995 F-150 Supercab. 4.9L and 5-speed 4X2.
Engine runs very well and is smooth through it's RPM Range.
Tranny seems to work fine with a little bit of hang-up going into 3rd sometimes.

At around 32 MPH I pick up a vibration. Sometimes it seems like it is coming from the front, sometimes the rear. The faster we go the worse the vibration is. It is so bad @ 65MPH that the stereo sounds like everybody is singing in Vibrato.

If I push in the clutch, put the tranny in Neutral, Accelerate or decelerate the vibration remains constant and is dependent on road speed. And it is loud...very loud. A growling sound.

I suspected drive shaft issues as the tires are new, so we jacked the truck up, put her on jack-stands and blocked the front wheels and climbed under for a look.

All of the U-Joints and center carrier bearing are tight and appear to be in good condition. No play and no noise. We started it up while the wheels were off the ground, and watched the drive-shaft for any evidence of movement or imbalance (drive-shaft whip). Ran her up to 50MPH and I was able to hear the noise and feel the vibration and it sounds like it is coming from the whole truck. I can't pinpoint it.

I work for a Chrysler dealership part time as a driver, and asked our service manager to check the balance on the new tires. The balance was fine on all except one and they rebalanced it. The vibration has not changed.

So, anybody ever experienced this or have any ideas?

Thanks for your input and help in advance.

Steve

 

My mother had the same truck, had a vibe that started at 45 got worse at 50 but was gone by 55. I did the same thing you did, jack the rear up and run it. If you can't see the shaft spinning out of round, try holding a stick against the shaft. If the shaft is good, the stick wont bounce off when it touches the shaft. You should be able to hold the stick on the shaft relativey easy. Since this truck had 130k on the original joints and carrier(which still felt good and tight) we had the shaft balanced with new joints and a carrier and the vibe went away.

 

I'll try that. Thanks for the advice.

My vibration does not go away...it just gets worse, the faster you go.

 

All of the U-Joints and center carrier bearing are tight and appear to be in good condition. No play and no noise.

The u joints can look and feel tight but have one cap in the bunch that has ran dry and has rusty needle bearings in it. Only way to know if the u joints are all good is to remove the shaft.

The only reason you'd suspect your drive shaft itself spinning out of round IE; "bent" would be if you hit something with it, high sided on it on something. Could have thrown a weight but you'd see were it was if you looked close. Drive shaft balance weights are spot welded on, because of this it would be fairly obvious if it was gone.

I'd start by removing the drive shaft and fully inspecting the u joints, should pivot smoothly with no binding in both directions with no play.

If you find the u joints, all the caps on em are good then I'd suspect a axle, pinion or center carrier bearing is well on its way out.

 

It's very unusual for a driveline problem to be consistant with throttle application, generally hitting the gas will tend to smooth it out.

I would look for problems in the rear axle, front hubs, etc. I've never seen a bent axle but it's possible, maybe a way out of balance drum, hard to say, but you need to look other places then the driveline.

 

I'm betting on a seized u-joint.. Nice and tight? Most likely rusted tight..

 

I think I may have found the problem...and it's not going to be easy......

The night before last, my wife hit a deer with our 2005 Dodge Grand Caravan. I had to run down to bring her home. 16 Miles of highway (4-Lane) driving each way. Vibrating all the way. I noticed that the vibration was always present but varied in intensity, regardless of road speed/engine RPMs.

When we got home, and pulled in my driveway, we heard a very loud BANG! I thought the tailgate had come open. A quick inspection showed the tailgate closed. I crawled under the rear of the truck and found the spring hanger bracket, that I had noticed somebody boxed in with 1/8th inch steel plate days ago (I remember thinking, "If that ever breaks it is going to be a pain to replace"). That son of gun broke.

So, I am thinking that this may be what was causing the vibration (drive-line angle?). I hope. My metal working skills are minimal and this is going to be a huge pain in the buttocks.

The plate steel is welded right on top of the bottom 2 rivets. I knew it was going to take some grinding to get the rivets out but this is nuts! The funny part is that some previous owner probably paid some moron with a welder big bucks to screw this up.

 

These spring hangers are well known for rotting out. The front leaf spring hangers are designed somewhat different and do not seem to rot like the rear hangers.
They are easy to replace. Check your local spring shop or NPD or LMC
They are not really expensive and it will take about 2 hours to swap out both and that allows for the banging and cursing when you try to get the bolt out of the shackle.
Grind off the old rivets with an angle grinder or whatever you have and use grade 8 or 9 bolts to re attach the new hangers.
Not sure that if that is the source of your problem though. I am sure I drove mine for a few days before I realized that one of my springs was up trying to push through my box before I replace my hangers and I don't remember any vibration.
Let us know how it works out

 

You didn't read my post. Go back and read it and you'll see that my replacement will be significantly more difficult than it should be. I do appreciate you input though. Thank You! It is nice to know so many folks are willing to offer guidance to complete strangers who's only similarity is ownership and hopefully love of these old Ford trucks.

I searched the web. I searched all of these catalogs I have (NPD and LMC Truck included) and I found the best deal at:

Ford F SERIES 3" Rear Spring Hanger/Shackle Assembly Kit, Complete, REAR OF REAR SUSPENSION BOTH SIDES**FREE SHIPPING**

$130 for everything needed for both sides with free shipping! I just ordered them and now I guess I'll watch for the brown truck to come by next week.

Somewhere in one of these threads on this site, somebody posted the same link I just posted and I followed that link. To that poster I say. "Thank You! You DA' MAN!".

Hopefully, this will fix my vibration. Either way, I'll post and let ya'll know.

 

I really don't see how this broken spring hanger can be the casue of your vibration. I think it's more likely a result of the vibration, not the other way around. And tells you that the vibration is likely coming from the same corner as the broken hanger. I would check the axle on that side.

 

My son said he thought the vibration started on that corner. I'll check it out when we have it torn apart. The old mount is completely rusted. The only rust on the truck. The steel plate they used to box it in is in very good condition however......what a PITA this is going to be.

 

Well if you have a broken spring hanger , thats going to throw off you drive line angle , pinion angle & thrust angle . When you fix the hanger i would have a good look at the u joints & yoke ...Lew

 

kcOrey....I guess I missed that last part about being welded over the bottom rivets...sorry
Looking at the time of my post, I was likely still on my first coffee.
In any event, I hope it doesn't give you too much of a hard time.
Keep a cold one close by just in case..

 

I have the exact same vibration from about 40-60mph and I have been chasing it for a couple months now. I did change all of my u-joints and have checked all of my wheel bearings. I have isolated things as much as I can to test and it's still there. Hope someone figures it out. Bugs the **** out of me!

Aaron