Hey everyone,

My dealer is chasing a vibration on the X, and I'd like your thoughts on the matter. Six months ago I had the driver's side manifold replaced at Lincoln of Concord, NH because of broken manifold studs. Immediately after this I noticed a loud shuddering noise at certain RPMs on the highway. Engine load doesn't matter; it would happen accelerating up or coasting down a hill when the engine RPMs hit around 2,200, and at certain intervals as it gets higher. Seems to only happen on the highway though. Shortly before this was done I had my rear tires replaced with new BF Goodrich Rugged Terrain tires in the stock 265/75R16 size.

Since the dealer is 130 miles north of me I haven't taken it back there since they replaced the manifold; I figured I would simply have the issue addressed when I was visiting my parents in Concord and had the time.

Fast forward to last month and I had the remaining two front tires replaced with identical BF Goodrich Rugged Terrain tires. As soon as this happened I started having a noticeable vibration on the highway whenever I get above 65 MPH. It sometimes fades in and out, but it feels to me like a tire problem, so I've been taking it back to this dealer repeatedly for them to balance the tires. Each time they do they have a hard time getting them to balance, and so after the third time they scheduled a time with a local tire shop to balance the tires at their expense. This was completed with no change in the vibration, and at this point I'm getting frustrated.

Friday I took it up there and spent the day there while they tried to figure it out. The tech took a drive by himself and came back reporting that it was a driveline issue. He also insisted that the vibration could be caused by the "aggressive" tread on the tires, which is something I vehemently disagreed with. We went on another drive together, and once we got on the highway he noticed the same vibration that I've been having trouble with. The tech wanted to dig into it, but he thought it was driveline related and I told them to go ahead and figure it out. He spent half the day on Saturday with no success, and he attempted to shim the axle to bring the pinion angle into tolerance. This morning I got a phone call asking for consent for them to send off the driveshaft to a driveline shop to see if it needs to be balanced or possibly rebuilt to the tune of $650.

They are insisting that it's not the tires, but with no play in the U-joints I have a tough time believing that my driveshaft would have come out of balance. What do you guys think?

 

What pressure are you running?

 

Factory spec 45 front, 55 rear.

 

How many miles on the truck?

 

118,000 miles.

 

I have the same tires though 285 in size and they always vibrated when the pressure was high. At 42Lbs all around, it's better but at higher speeds, it still vibrates. Your pressures should be ok.

 

I can't believe that the stub and slip joint is bad at that milage, that's what costs the most, I just had mine balanced and new u-joints at a little over 220'xxx and we just packed the stub and slip with grease and all is good. Just make sure they take it to a reputable drive line shop if that's the path you take.
The other thing I would check is for a bad tire and I'm not talking about balance, if this all started after the 2 new tires I would elimanate that first. I would take one tire off at a time and replace it with the spare and see if you notice anything different. Just some ideas!

 

I agree with swapping out the spare tire on each side to see if the vibation changes or goes away,,,,

 

It in the rear or you feeling it in the wheel? I am guessing you feel it when you are 2WD only since you said you were doing 65+. Reason I'm asking is that I know a lot of people pull the front drive shaft when removing manifolds for easier access. Did it get dropped? But if it's rear and in 2WD that is kind of a moot point.

Have so many "solved vibrations" in my truck and root cause list in no particular order were

Pinion Angle
Bad Tires
Bent Yoke on drive shaft
Bad rear wheel bearings

All had separate vibrations at different speeds, some audible some not, Took all 4 of the above to get mine vibration free. But mine was a hot mess with many recent mods at the time. My short list anyway.

 

That's good to know, when I was towing out here I had over 5,200 lbs on the drive axle and had my first set of Rugged Terrains aired up to 80 PSI and never noticed any vibration. Of course the pressures were that high empty it may have been a different story.

I don't think there is anything wrong with the slip joint; I took it off at 114,000 miles and greased it up before moving out east. Of course I didn't inspect it for wear because it wasn't vibrating at the time!

I thought about that, and I also thought about seeing if it would vibrate if I removed the driveshaft and drove it in front wheel drive. But it's been at the dealer since Friday and they are doing the guesswork at this point. I strongly feel that it's the tires, but short of swapping out for a very old and weather-checked spare I haven no way of troubleshooting it.


That was my first thought with the noise, but as you mention the front driveshaft doesn't spin in 2WD. Pinion angle was one of the first things the dealer checked, but they had no luck solving the problem. No shaking until the tires were replaced, and absolutely nothing has whacked or molested the driveshaft since I've owned it. The tech suggested pinion bearings, but at the point they are at I'm assuming that's been checked for.

 

Here is the thread I started for a vibration issue. Lots of really good info, hope it helps.

https://www.ford-trucks.com/forums/1...vibration.html

 

I know this is going to sound odd, but... I have bent the skid plate over the transfer case several times. Every time it causes the truck to vibrate. When I take it off and bend it back the vibration is gone. How long have you had the new tires? Has it lessened over time. Seems like when I rotate and balance mine( Toyo AT 285/75) the kind of vibrate for a few miles. I had my front drive shaft serviced and balanced at 117000 mile because when I lifted it I found that it was frozen, cost $115 with new u joints. Just some thoughts, hope they help.

 

I have 152k on my Ex, only vibrations I have ever had have been caused by tires, every time! I would make sure you WATCH the tires spin on the balancing machine. My tire shop guys know I am **** and are supportive of it, I usually help them as we go, now granted this is a small shop and I know the guys that own it and they know me. The last set, had a bad tire, it balanced, but it vibrated, took it back, we watched it spin, tread was jacked up, AND looked like a slipped belt, new tire, no vibration.
Also, my 02 dually, had spacers between the rears to fit larger tires, the spacers need to be lug-centric, as they are to far out on the hub to be hub-centric, I would look at tires, maybe find cheapo stockers and swap them out,,,

 

This might not be possible but if you can swap all four wheels with another vehicle, this might be an interesting experiment. Also just moving the spare around from corner to corner as someone mentioned.

About balancing, I agree with comments about watching the tech do the balancing. Also, you might want to shell out the money to have another shop balance the tires. Also about balancing, most shops will just stick weights around the outer rim edge. A good balance job will include weights stuck on the inside of the rim too. One last thought, if you have a rim with a massive succession of wheel weights covering say 1/4 of the rim lip, then you have a crappy tire and they should replace it.

 

Balise Ford called right as I was getting out of work, their driveline shop says that I have a bad slip joint. $525 to fix including dealer labor. I suspect this will fix the loud humming noise I'm hearing at highway speeds, but the vibration feels like tires to me.

We'll see.