need help identifying vibration source

[Briar Hopper]

Had a new set of Michelins put on today. Still getting a strange vibration in the truck, feels like it's coming from the front. It only does it between 11mph and 19mph. Either accelerating or decelerating, braking or coasting, it only does it in that speed range.

What am I looking at? U-joints seem to be fine, no play in them, checked them ALL... brakes were new 6k miles ago. Rotors are straight. No brake noise. Can't be the clutch or flywheel.

Front wheel bearings? I just changed the lube in the front diff, and the transfer case, then about 500 miles later, this starts happening. I don't have any leaks from either one... .

 

[work2muchplay2little]

Have you tried checking the tie rods, drag link, track bar, and control arms for excessive play? Might also try a front to back swap of your tires/wheels. Good luck!

 

[JTBMC]

A friend of mine had 6 new D rated 235x85x16 Dunlaps installed on his 99 Power Choke and has a vibration at low speeds with high air preasure 80 pounds and is down right scary at high speeds 70-80, mph. At 55 pounds rear and 60 #'s front the low speed vibration is gone. He went with D's rather than E's becouse the Tire Guy told him they would improve the ride of his 1 Ton 4x4, now he's stuck with tires that are wearing fast and unstable pulling 10 tons of Hay & trailer.

 

[willyslover]

"Still getting a strange vibration in the truck". . prolly not tires IMHO



Tom. . did ya check to carrier bearing play on the pinion. . all those launches at the drags might have some wear factors showing up now. .

also the front shaft u-joints might need inspection if you have used 4x4 for launches

also another idea. . you have the two piece drive shaft. . did ya look at the center carrier. . [i know ya said it came from the front, but those damnn things transmit all over]Just some thoughts to ponder

GaryON EDIT... Tom just thought . . years ago I had a similar expierence on a 56 Chevy drag car. . turned out to be the damnn U Bolts on the spring hangers. . just an FYI

 

[Briar Hopper]

Thanks, Gary,and everybody, that's a good checklist. The weird thing is it's not doing it NOW... It didn't do it on the way home from work, it didn't do it coming in to work tonight. STRANGE !

These are Michelin 235-85R-16 LTX M&S, "E" rated... same as stock. 60 psi in fronts, 50 in the back. remember, this vibration ocurred both shortly before and after the new tires...

I have only 12 "launches" under my belt, at 3 drag strips, none in 4 wheel drive. Universal joints front to back was the first thing I looked at. Nada. No play in any.

I'm going to jack up each front wheel individually, and spin it, see if it grabs, then I'll know if I have warped rotors. Might also bleed some air off, see how the tires react to lower psi.

And, I guess I'll have them rotated and re-balanced, if nothing else.

 

[willyslover]

Tom... IMHO you'd be wasting your time on tires [rebalance/rotation] if it was there pre new ones. .



don't forget the ball joints . . we have a weeeeeek set in our rigs

low speed is where a lot of the issues would show up on most of the named items

How about bent rim ?. . prolly would have showed up in new balance.

FYI I run 50 front and 45 rear unloaded pressure. . other wise I eat the edges off in the hills. . and you know how I like to drive the hills. . lol. . I never wear out the tires, I grind them up

 

[Briar Hopper]

You're right about the tires, except for two things, 1) they had a new kid balancing them on the Coates digital, he had trouble doing it right. 2) The first time they balanced them was on an older Coates (or so they claimed) and it was messed up, didn't get them right. They're still not right, I'm getting some tire shake at over 60mph...

Ball joints I haven't checked, that's one thing for sure I need to do... maybe time to order a couple of Luke's Links...

You drive like I do? Like Junior Johnson with a load of lightnin' and the revooners after him? It ain't fun unless you can hear them 4 Michelins out back barkin' like dawgs... . You'll have to ask Stack'd 'n' Jack'd (when you see him at Tulare) how he likes riding the mountain roads in Kentucky with me, heehee. Seems like he can hear the tires, and I can't.

 

[willyslover]

love to drive a dually all crossed up . . as the old saying goes ya haven't lived 'till ya stear by the rear and the loud peddle

agree that you'll need to redo the balance. . however at very low speed you shouldn't feel a vibration unless they are really in deep trouble. . more a square tire ride at low speed, again Tom MHO

 

[Briar Hopper]

Square tires? LMAO That's B. F. Good & poor, not Michelins. Fred Flintstone, I ain't. Seriously, I do follow what you mean, and agree with you, on the tire balance thing. The low speed vibration just doesn't have a logical connection to the tires, whereas the high speed vibration is instantly recognizable by the "S. O. P. meter" as being a tire slightly out of balance.

 

[fest3er]

Originally posted by Briar Hopper

Square tires? LMAO That's B. F. Good & poor, not Michelins. Fred Flintstone, I ain't. Seriously, I do follow what you mean, and agree with you, on the tire balance thing. The low speed vibration just doesn't have a logical connection to the tires, whereas the high speed vibration is instantly recognizable by the "S. O. P. meter" as being a tire slightly out of balance.

Low speed vibration could be a bent wheel. High-speed vibration might not be out-of-balance, but out-of-round. When they have the tire on the balancer, look to see if it is 'round' as it spins. If it isn't, have them spin the tire on the wheel 180 degrees and try again. Also, see if the tire 'wobbles'; if so, it's bent - dunno what to do about bent wheels.



I think my rear tires have walked a bit and are slightly out-of-round, but they only vibrate slightly at about 41 MPH. I also have a couple or three bent wheels, but I only notice that on rare occasions, in the steering wheel, at very low speeds.



A bad ujoint could also cause low-speed vibration, as could an out-of-round driveshaft - my front shaft went OOR within 10K miles of buying the truck new; it was one of the few things covered under warranty.



Good luck, Tom. Maybe I should invent a heads-up noise-to-sign translator that displays the appropriate signing on the windscreen for specific noises it can 'understand'. Things like tire squeal, turbo whine, roaring exhaust, screaming terrorists under your tires. That sort of thing. t just isn't fair that deaf folks can't enjoy the pleasure of annoying squeaks and rattles.



Fest3er

 

[Snow man]

If this vibration was a benr wheel ,the tire balancer guy should have caught it,during balancing. If its on the front,the sterring wheel should move back and forth slightly when its shaking,if you let go of it. Id suspect the U-joints too,or carrier bearing if its a 2wd excab.

 

[willyslover]

Tom. . don't remember year of yours, CRS ya know... I have my ol#1 still if you need pre rear wheel disk model rims [in case you find a bent rim, but I don't think that's it]. . I have all 7 of them still... with a 215 still mounted that has never been on the ground. . [I know you changed to 235] but if anyone in central Calif or close need some they can get ahold of me

 

[J Allan]

vibration

I had my truck in the transmission shop last week. For the longest time I had a vibration. I blamed it on the tires. To make a story short he told me that my drive shaft was out of balance. he fixed it and it rides just like the day I drove it off the lot.