Still Chasing That vibration

[dpuckett]

This is driving me nuts!!!!! I am about ready to sell my pickup. I have had this vibration that comes and goes for a few months now, and figured it was a combination of the transmission being worn out and a bad u-joint/out of balance driveshaft. Got the rebuilt transmission in (which leaks profusely around a PTO cover now ), and the driveshaft balanced (complete with 3 new u-joints), and guess what, I still have that vibration between 50-80mph. It is improved, but still noticeable, mostly above 70mph. It is quite livable from 50-70. Under 50 is normal. The front end has been rebuilt- new bushings and ball joints. It was aligned, but when I replaced the steering coupler, the wheel tilted to the right, which makes me question the rest of the alignment.



As for the vibration, that leaves tires/wheels. But, the shop owner says the tires are balanced. I did see that it had no wheel wobble/hop/shimmy on the balancer. I have not tried any known good/smooth tires, but what the heck else could be causing it? As of right now, it looks like we will have the only gas-powered vehicle at SOP, though it will be a Dodge (Dakota). I am about ready to stick a $3500 price tag on this thing and cut my losses. Sell my other truck for $2500, and get a pickup I can get in and drive and not have to do this stupid crappola.



Daniel

 

[TWorline]

Did you replace the carrier bearing as well? How are your rear differental bearings?

 

[pepecat]

yeah well is the vibration just an annoyance or ? I had my tires and wheels "balanced" again at rotation time, and mind you these are Brand new Highway tread smooth tires! They still shake pretty bad at highway speeds sometimes, esp above 85 mph. The rims are Alcoa 16x7s!!! They are straight as an arrow! Well anyway I think if it's not doing any damage, just let er be and drive on!

 

[Ridgerat]

dpuckett where ya feeling the vibration? In the steering wheel, seat, floor boards?



Also, what kinda tires ya running? Could one be bad or slightly outta round?



Sounds like you've covered most things already. Did you replace the wheel bearings when the ball joints were replaced? Did it vibrate before replacing the ball joints/bearings?



RR

 

[dpuckett]

The vibration is NOT coming through the steering wheel, that is one thing I am sure of. LIke I said, I havent driven 10mi with the new driveline in yet- too much oil puking out the PTO cover bolt hole. I found I have a cracked case where the bolt threads in- time to pull it again, and I guess make 1 good transmission out of the 2 I have.



It seems to be coming from under the cab, or possibly rearward of there.



I hadnt thought of differential bearings. Front wheel bearings (and races) got replaced at the time of the rest of the front end work; rear wheel bearings are good. And yes, it had the vibration before the front suspension/ steering work.



Tires spun well on the balancer at however fast that is.



Thanks guys.



-DP

 

[MMiller]

Are you sure the case is cracked? Some of the pto bolt holes do go through the case I think, and unless a little sealant is on the threads, the oil will migrate out the bolt holes.



What is your pinion angle like? Is it appropriately lined with the drive shaft? Is this a dually? If so did the wheels get put on with those tapered nuts to get them all centered up?(there was a thread on this, Phillip knows all about it)



I would not think the diff bearings would make a vibration like a tire out of balance, more of a howl or moan would be more appropriate for something worn in the diff.



Michael

 

[JLabossiere]

A couple more ideas that you may want to look at.

-Do you have a steady bearing on the drive shaft?

-Transmission mount maybe getting weak.

-Exhaust support broken, I know how can that vibrate, but it happen to my parents vehicle.

-Belts may have started to split on the tires, hard to see sometimes and you don't feel it until you hit higher speeds. But if you run your hand along the face of the tread you would feel a slight bump.



By then you have gone over almost every inch of your truck and have new holes in the garage wall... then the harmonic balancer might have spun on the rubber gasket and added vibration that travels back through the drive line. Not trying to discourage you, just some other ideas to look at along with the diff bearings.

 

[PToombs]

Daniel, swap tires front to rear and see if it feels different. Like JL said, could be a broken belt in the tire. Maybe double check the u-joints are aligned, all yokes going the same way. If the slip joint is off some on the splines might do it. God luck, hope to see you at SOP.

 

[PToombs]

As of right now, it looks like we will have the only gas-powered vehicle at SOP, though it will be a Dodge (Dakota). Daniel

Hey! Want me to bring a 4bt and trans? We could do a conversion! Oo. Oo.

 

[pepecat]

Rear axle bent perhaps?? Philip had a bent one.

 

[Philip]

My bent rear axle didn't throw any vibration. It just wore out 4 new tires in 10K miles.



Jack up the rear axle and spin the duals. See if they are tracking straight. If someone put the duals on wrong and didn't line up the centering pin and bolted then down. You will have a bent rim. You might not see it on a spin balance. The rim is secured differently.



You say the vibration comes and goes? How are you feeling it. Threw the seat or threw your foot setting on the floor board?



Like Michael said. A bearing will give some vibration. But most of the time it is noise and howling. When they vibrate bad they mostly explode very soon.

 

[glhs]

Point the truck away from possible hazards and jack up the rear. Get it up to 85 mph or so and see what happens. If you have access to a dyno you could put it under load which might help.

Spring bushings worn out?

Bad rear end? My dads 93 D350 had the rear end rebuilt under warranty way back because of bent axles/bad bearings and it had about 50,000 miles.



Kurt

 

[dpuckett]

I have a 99 D80 axle under it with about 140K mi on it- no guide pin alignment issues (and outboard drums, to boot Oo. ). Tires in back have less than 10K on them, but that isnt to say I didnt get a defective one. So swapping tires front to rear is not doable right now- still have 1st gen wheels on front.



I have no transmission mounted exhaust support, so that isnt it, either



SPeaking of the h-balancer, the engine does have a shimmy/ shake at idle that comes and goes. I guess that could contribute to it if it does it under load. Sometimes it wil shake the whole truck, then smooth out, come back, go away... ..... DOesnt matter if I depress the clutch pedal or not.



Michael, the case is cracked around the threads of the lower PTO bolt, and I have enoh silicone glommed up around there to keep it from leaking around the cover, but it is coming out through the bolt hole. gonna see if I can find a rubber- faced washer to out under it and hopefully get it to stop leaking as bad.



-DP

 

[Philip]

Daniel get a brass washer that is used for a brake line. Rubber might flex out. That brass one will not.

 

[Regcabguy]

BFG tires.

Two years ago I replaced my tires with 285-75-16 BFG KO's. From day one I inherited a vibration that drove me nuts. Well,after too many rebalances,road force,etc. ,I replaced the tires with Toyo m-55's. Noisier that the BFG's but excellent ride quality and guess what? Vibration gone. I'm a Toyo fan from now on. Hope this helps somebody.

 

[dpuckett]

I have 2 quite used tires on the front; new Mastercraft Courser LT radials on the rear (had 6 of them on my 91 with no problems). I took it for about 35mi up the interstate at 70+ and had no vibration to speak of. A little bit came and went that could well be attributed to the road. But at 80+ the vibration gets real bad, and seems load related. Then again, 85 is speeding ticket territory... .



Philip, I got a rubber washer and put a steel washer on top of that. The transmission is coming back out before I go to SOP3. The old one only needs reshimmed and a different top/shift tower put on. No big deal overall, but I still dont like it. I found a 4x4 transmission for $250 that is supposed to be in excellent shape, 105K or so. Getting a good case and 1-2 synchro assembly (yes, I put the old cracked one in there, part of the reason it is coming back out) is worth that. I may have parts in a little bit.



-DP

 

[832]

I know how your feeling about that vibration. I have one from 40-55 mph and sometimes is worse on certain days. How do you know if your harmonic balancer is bad? Because mine does have a vibration at idle in park.

 

[IRoss]

I have a similiar situation i my truck, a rocking vibration at over 70, which actually got worse when I had my wheels and tires (Bfg mt)s balanced. I am fairly convinced that this is a front end issue myself since my rear diff and driveshaft joints are all fairly new as well... .

 

[JLabossiere]

How do you know if your harmonic balancer is bad?

Mine was easy, it was actually falling apart . The outer section of the balancer falling off the inner section, luckly it was coming apart towards the engine. Had the timing cover to hold it from coming right apart until I got home to repair it. Bad part was I had to replace both. To find out otherwize I think you might have to remove the tappet cover and rotate the engine to TDC and if the timing mark is out, the balance would be out. Now I am kinda fuzzy on that part, there is other's who would know better on what to look for.

 

[GGott]

Hi there, Did all the things you did too. Found my vibration was a hub. The hub and mounting flange were true with a dial indicator, but the stud pattern was 79thou off center, this was a factory screw up and no doubt the two previous owners went through all the crap I did trying to find this vibration. It could have been fixed on warrenty when the truck was new. Hopes this helps you.