I'm lost with this driveline hum/vibration...

[pj8847]

Hi all,

Before I start, I'd like to say I have searched the boards for my problem before posting, so as not to waste anyone's time on something that has already been covered... none of the results seem to "fit" my problem though...

I have been plagued with a vibration/hum that appears to be coming from the front end that gets louder/worse as I increase in speed. The problem becomes noticable when I reach speeds of approx. 50mph and steadily increases in volume and in speed as I accelerate. perfect way to describe what it sounds like is a "Jake Brake" but not in volume...its not loud at all, its just there, whether I keep it in drive at 60mph, or even if I shift into neutral, its there.

Now I have already ruled out several things, which are:

its not anything in the drivetrain ( Engine is rebuilt... 60k, tranny is new, transfer case is new, drive shafts ) as I had all inspected and all passed ( front/rear shafts were balance tested, tranny is in perfect condition as well as transfer case. I replaced all of the universal joints anyways just to be sure )

its not tire balance ( had tires checked and rechecked and speed/load balanced twice, and rims are perfect, no signs of warpage, even went from the stock 235/75/r15 up to brand new 31" x 11.50's... no change, even after several alignment checks, and BTW... the 31 x 11.50's went on fine with no rubbing and no tweaking of the suspension, truck was at stock height, I was shocked... )

its nothing with the braking components ( rotors are fine, no binding, nothing out of round or warped, calipers are new and mounted firmly to their designated positions )

its not the hub bearings ( they are fairly new with absolutely no signs of wear, smooth fluid movement, no play )

its not the front differential itself ( replaced it with a new unit straight from ford, everything checked perfect )

rear diff. is solid, no signs of abnormal wear, no excessive play in any internals.

all fluids throughout truck are new and of proper types.

So now I'm left to figure out if I have a bad half shaft ( vibration/hum *feels* like it comes from passenger side while driving, but passengers in truck say it *feels* like its on the drivers side ) But I have had both shafts checked and both appear to be in excellent shape. ( they should be, as they were also replaced with front diff. ) Only thing I can think of is that one may be slightly unbalanced, which would require me to remove them and have them checked.

There is one thing about the vibration/hum that is strange, when driving on a road where there are slight peaks and valleys in the pavement, as the truck rises and settles on its suspension during driving, the vibration/hum dissappears for the split second that the trucks suspension is reacting to the roadway. thats why I'm thinking I may have a bad half shaft, or possibly a worn slip joint on the rear drive shaft? But again, rear shaft checked ok, and all suspension components are solid ( almost all new )

Any input on this little problem would be much appreciated, as I'm left to scratch my head and ask myself what is wrong with this Exploder, because otherwise the truck is in mint condition even though it has hit 200k!( wish I could post pics, she's a beauty... but i've tried and failed, damnit...heh heh... )

Thanks in advance for any/all help, much appreciated...

 

[Rhett]

So now I'm left to figure out if I have a bad half shaft (

Well, has the truck ever been wrecked?

Your post is really confusing to me...but I am often easily confused. At one point you say the shafts have been "balance tested" and the u-joints replaced. And then you go on to say that you suspect the shafts *are* the problem. (????)

 

[BuffaloXplorer]

I would have jumped on the bad u-joints and or front driveshaft - but if they've been tested & OK'd, then i just do not know what to tell ya....you said wheels are balanced, rotors are OK....hmmmmm...have you looked into the torsion bar adjuster? I'm not sure if that could cause vibration but it could be due for a change after 10 years

 

[Creager]

is it a manual tranny? i bet you the output shaft bearing is about to go out. Thats exactly what mine did. at first it was just a noise getting louder and louder, then finally the faulty bearing put enough drag on the tranny to where it jammed up the shifter and everything.

U-Joints are also known to make some funny noises when those needle bearings get all wacked out. i would start by checking those u-joints out... if they have zerks equiped put some greese in em. If the sound doesnt go away i would start looking towards the rear of the tranny.

 

[pj8847]

Thanks for the quick replies... Thats why I love this site, it and the poeple on here just kick a$$ with all the help and knowledge offered.

Well, has the truck ever been wrecked?

Your post is really confusing to me...but I am often easily confused. At one point you say the shafts have been "balance tested" and the u-joints replaced. And then you go on to say that you suspect the shafts *are* the problem. (????)

The main drive shafts from out of the T-Case to the front and rear diffs. were balance tested, the other shafts I spoke of are the 2 small half shafts that go from the front diff. to the wheels, sorry for the confusion. As far as the truck being wrecked, worse wreck this truck has ever seen was the slaughter of an innocent shopping cart in the grocery store parking lot... ( people REALLY should put them back where they belong... heh heh )

I would have jumped on the bad u-joints and or front driveshaft - but if they've been tested & OK'd, then i just do not know what to tell ya....you said wheels are balanced, rotors are OK....hmmmmm...have you looked into the torsion bar adjuster? I'm not sure if that could cause vibration but it could be due for a change after 10 years

I've gone over the supension and drivetrain with a "fine tooth comb" and everything is A-OK. I even had the truck to several shops that I have friends at and to two dealers, no one can find out where its coming from, they feel and hear it on the test drives, but can find absolutely nothing causing it.

is it a manual tranny? i bet you the output shaft bearing is about to go out. Thats exactly what mine did. at first it was just a noise getting louder and louder, then finally the faulty bearing put enough drag on the tranny to where it jammed up the shifter and everything.

U-Joints are also known to make some funny noises when those needle bearings get all wacked out. i would start by checking those u-joints out... if they have zerks equiped put some greese in em. If the sound doesnt go away i would start looking towards the rear of the tranny.

I knew I forgot to mention something, it's an automatic trans. which is new, as well as the T-case. The truck was doing the same thing before either was replaced, thats why I'm pulling out whats left of my hair, almost everything under the truck and under the hood has been replaced, and it still does it. I have been reading however there are alot of people with similar vibration probs. that not even FORD themselves can explain, I'm starting to think I have the same "phantom vibration", and its driving me nuts.

If this keeps up I'm going to have to pull out my Camaro from temporary retirement and drive that until I figure out whats wrong... ( I REALLY don't want to do that, a small block 400 pushing 425hp is NOT, I repeat NOT wallet friendly on 103 oct. fuel these days! And when I drive that, my foot seems to gain several pounds... don't know why... )

 

[griggs]

What engine do you have? if it's a 4.0L pushrod then I can add some experience. I'll wait for your answer.

 

[pj8847]

What engine do you have? if it's a 4.0L pushrod then I can add some experience. I'll wait for your answer.

Actually it is in fact the 4.0l pushrod engine in my explorer, I'm not sure what that could mean, but any experience in this situation will be knowledge gained... and hair...lol

 

[BuffaloXplorer]

Bad motor mounts? Could possibly cause excessive vibration (?) - i know, it's a stretch

 

[Creager]

Bad motor mounts? Could possibly cause excessive vibration (?) - i know, it's a stretch

i would second that, probably the Tranny mount actually. Thats more likley to wear.

 

[pj8847]

again, thanks for all the replies so far...

Motor/tranny mounts were one of the things I had suspected to possibly be contributing to the problem at first, so those were checked when I had the drive shafts checked, Tranny mount is new ( although that means nothing some times ) and motor mounts are solid ( were replaced 30,000k after new motor was dropped in, because I had forgot to get new ones then. )

I even went as far as removing that stupid 5th shock ( or dampener ) that is monted to the rear and frame, with no change, so I put it back in.

I also thought it could just be the driveline resonating through the frame and up into the body, because the body bushings are original, they don't appear bad, but, they are 10 years old. I wasn't going to worry about them though, seeing I was thinking about a lift, and if I do that, I want to pull the body off the frame anyways, because if i'm doing a body lift, i'll want to lift the suspension too, and a solid axle swap is the only way i'll go... might as well get the frame set up and install everything I want to do once the truck really starts to show her age, but she's not ready for that yet. ( welding and painting the frame is alot easier when you just have the frame in front of you, while the body sits on blocks out of the way )

Untill that time comes, I need to track down what this is, because there is no such thing as "good vibrations"... heh heh

 

[griggs]

A 4.0 L OHV huh. Well I had a 96 X same engine auto trans 4 X 4 Control Trac that had a humm/vibration into the floor boards and gas pedal at just some speeds that could not be removed. Observed the same thing in another same X. Dealer mechanics drove mine and said "thats the way they are". I blocked up checked for anything worn, changed u-joints R&R the damper weights and nothing would fix it. Some people did not notice it but I sure did. Unsat. It has something to do with that engine combination. Finially sold at good price to someone who did not notice, or care, and bought a 97X with 5.0 V8. No more problem. Also interesting that Ford offered a 4.0L Overhead cam engine in later year which they said was smoother. Hum. Thats my story.

 

[ExplorerDMB]

I even went as far as removing that stupid 5th shock ( or dampener ) that is monted to the rear and frame, with no change, so I put it back in.

That shock is the Lateral Shock. It's for the rear differential/axle so when you take it from park to drive, it doesn't "jerk/pop" too bad.

-Drew

 

[01EB5.0]

As tires wear they cause a hum or sort of a "wah-wah" sound and it gets faster as you drive faster. My 5.0L AWD has been getting worse and worse for a while...my tires are also almost bald. My 95 did the same noise as it's tires wore too. I am sure once i get new tires my truck will be a lot quieter again.

 

[pj8847]

A 4.0 L OHV huh. Well I had a 96 X same engine auto trans 4 X 4 Control Trac that had a humm/vibration into the floor boards and gas pedal at just some speeds that could not be removed. Observed the same thing in another same X. Dealer mechanics drove mine and said "thats the way they are". I blocked up checked for anything worn, changed u-joints R&R the damper weights and nothing would fix it. Some people did not notice it but I sure did. Unsat. It has something to do with that engine combination. Finially sold at good price to someone who did not notice, or care, and bought a 97X with 5.0 V8. No more problem. Also interesting that Ford offered a 4.0L Overhead cam engine in later year which they said was smoother. Hum. Thats my story.

Interesting, did you ever shift into neutral at the speed the vib/hum happened and allow the engine to drop to idle? if so, was it still there even in neutral, mine is, its there even if the engine is shut off ( i know, not safe to do at 55-60mph, but at 3am where I am, its just me on the hiway ) and coasting at 55-60 mph engine off, its still there, thats why I thought it might be the rear diff or driveshaft since the front doesn't spin in 2WD... but it sounds like it comes from the front, unless of course its just resonating through the driveshaft and t-case making it appear to come from the front. Its definitely noticable when it starts, my 5 yr. old even asks "daddy, whats that sound?"

P.S. earlier I was out driving it and took the truck up to 85mph, vib/hum disappears after about 75-80mph... strange... i never drove it faster than 65mph since i noticed the vib/hum, afraid whatever it was i'd make worse, but nope, smooth after 75-80mph, doesn't make sense... starts at about 50, gone after 80? However, the vib/hum is almost unbearable at about 70mph. I'm stumped...

 

[pj8847]

Just a tiny bump

 

[scott93EB]

I don't know what could be making the noise, but about it being at certain speeds could be because everything has a natural "frequency" that will do weird things. Same principles as that clip of the old bridge in the wind(may not have seen it), soldiers walking across bridges causing them to bounce( a lot), swinging, etc I'm sure you get the idea, at the right speed somethings shaking just right to make the vibration the worst. I know this doesn't help with what it is but just why at certain speeds.

 

[XtothaZ]

Sounds alot like the problem I have

up to 55 it's a nice ride but between 60 and 70 I'm it's shakes like hell! over that and the procomp shocks smooth out and the truck is really nice handles freeways great at even 85. but most of the time I need to be going 65 which is where the peak vibration occurs. I think this is going to get expensive. I'm thinking of going down the list of the most probable causes and continuing untill the problem is solved.


New Tires
Tire/Wheel balance
Shocks
Wheel bearings
Controll arm bushings
Ujoints
Motor Mounts
Tranny Mounts
?
?


Does this list look to be the right order???

Chris

 

[pj8847]

up to 55 it's a nice ride but between 60 and 70 I'm it's shakes like hell! over that and the procomp shocks smooth out and the truck is really nice handles freeways great at even 85. but most of the time I need to be going 65 which is where the peak vibration occurs. I think this is going to get expensive. I'm thinking of going down the list of the most probable causes and continuing untill the problem is solved.


New Tires
Tire/Wheel balance
Shocks
Wheel bearings
Controll arm bushings
Ujoints
Motor Mounts
Tranny Mounts
?
?


Does this list look to be the right order???

Chris

I know that list all to well, replaced everything on that list plus alot more, still the problem persists. I'm at the point of possibly selling the Explorer, seeing as the problem can not be found. Makes it difficult to continue to trust the truck when I have my kids in it. I've had a few nice offers for it already, so I may just let it go while I can. Still undecided though.

 

[witchdoctor]

don't know if this will help but i'm having similar problems. i guessed that maybe the rotors are slightly out of balance. i took off the tire, moved it back two lug positions, and put it back on. problem is not totally gone but is much better.