Vibration at High Speed Causes? (1 Viewer)

Joined
May 9, 2010
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So since I've bought my FZJ80 4 years ago, I've always had a slight vibration at 60-70mph. Sometimes its mild, sometimes its bad. A little digging has said the variation of intensity could just be harmonics but I'm happy to accept it as a symptom. Detailed symptoms is it shakes the whole truck, I think its in my seat (so leaning towards rear) but its hard to isolate.

I'd love to see if we can get a thread listing all the possible causes of vibration at high speed for me and future mudders to help check off. I'm going to list the causes I know and found (plus my specific resolutions).

Possible causes:
- Bent Wheel (I've gotten 2 sets of tires since owning and countless balancings and no one has ever mentioning a bent rim. Of course still possible, but seems unlikely)
- Out of balance tire or alignment (See above)
- Bent Axle (Going to be taking the two rear axles to a shop to check for runout)
- Bad Shock (Brand new Toyota shocks just put on, the vibration is much better but still there)
- Bad wheel bearings (Replaced some time ago, no change)
- Bad U-joint (@rifleshooter suggested)
- Bearing Preload Off (@Eicca suggested)
- Dry spindle bushings (@RAYJON suggested)
- Bad axle pinion bearings (@RAYJON suggested)
- ?

Could an out of balance drive shaft cause this (specifically at only high speed)? Or what ever causes are there that I can check before putting this all together.

Edit: I'll continue to add causes as they come in to keep the first post full of info for others.
 
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Joined
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Helena MT
Is it at a specific RPM/speed? If yes....Climb under and look at them/shake the shaft looking for play. I had one go bad this year and it matches said discription. If one is in question pull the shaft and you will easily be able to feel the bind.
 

Eicca

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Check the wheel bearing preload, especially if serviced/replaced. They can come loose. Mine were loose and making my out-of-balance tires behave very strangely. I'd get dang scary vibes at 60mph sometimes and not other times.
 
Joined
May 9, 2010
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@rifleshooter yup. Always at 60-70 and around the same RPM (I think 3.5k ish, but I'm guessing) Awesome, thanks for the info. I'm getting ready to drop the transmission in 2 weeks to replace a bad rear main seal, so it will be a perfect time to pull them and check.

@Eicca I have replaced both front and rear bearings (at different times) and rechecked the preload after a few k, but its always possible I missed something. I've actually pulled all 4 axles this weekend to take and get checked for run out. So I'll be sure to check the preload carefully when I replace them.
 

RAYJON

Get a bigger hammer..
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basics.. 80 series arn't that complicated, check transfer case bearings for play, u joints for play and not moving smooth (any at all replace them) then axles pinion bearings- wheel bearings

tires and wheels are always first, done
wheel bearings next--- jack it up and look for play in the bearings again.. make sure the fronts are preloaded per spec..
u joints..

check the front spindles, if they are dry it will cause what you are talking about, the spindle bushings can get dry and warn, will cause mild vibration over about 60mph..

if you have a center diff lock, lock the center diff, pull the front drive shaft and drive flanges on the front wheels and take it for a drive.. you should be able to isolate front or rear that way,

another thing, how many miles are on it, if it has really high miles check the preload on the rear carrier, a loose or bad pinion bearing can cause vibration at speed..

good luck..
 
Joined
May 9, 2010
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@RAYJON. Lots of good stuff. I've got about 215k on it, but the vibration existed when I bought it at just around a 100k.

I'm going to pull the transmission in a few weeks to replace the rear main seal, so I'll take a lol at the u joints then. I'm guessing that would also be a great time to check the pinion bearing as well.


The good news is I tested all the axles tonight and the worst runout was less than 0.004 (FSM says max allowable is 0.005in)

My $35 runout tester. Worked far better than expected.

ImageUploadedByIH8MUD Forum1413848617.719069.jpg
 
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My vote goes to u-joint. I had very similar symptoms to what you are describing (specific highway speed) in a couple of my 4runners. Easy and cheapish to fix, so not a bad place to start.
 
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At 60-70 mph a tire related issue will be a thump-thump-thump as opposed to a driveline related issue which will be a buzz-buzz. Remember, driveline parts are spinning more than 4 times tire speed.
 
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LINUS

Waiting for the Great Pumpkin
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How about:

-Pinion angle (you don't mention if you are lifted)
-Drivelines aren't greased (supposed to hit the zerks with a pump of grease every ~10-12K?)
-Bushings (At youngest these are 15 y.o. parts, rubber especially grease-soaked, is gone)
-Basic wheel bearings (miles, maint., usage?) -Grab a wheel still bolted to but jacked off ground & shake like a SOB -find any play?

Then there's the individual 80 realm:

-Past owner maint/neglect (AKA "I'll do it someday"---)
-Individual usage undisclosed that was outside what you see (whole axle shell bent (FR bends-did 1 myself), diff that ran dry, then a PO ran on gears awhile before fixing say axle seals (birf soup?)
-"Creative" induced vibes - the all encompassing of self made parts in a lift or whatever - we all have seen something in this group.
-Lift related, but how's the 4 wheel alignment? Bent frame by a PO possible?

As to most all parts wear - The old "shake like you mean it" or else 'apply pressure while watching/listening close for play' - that's worked for me when it comes to u-joints. if you like, use a band wrench (or screwdriver through end) to see driveline rotation wear, I let mine wiggle but not crazy loose. Think boxers, not tighty-whitey or 'going Commando'.

It'll only be as smooth as much you obsess trying to track it down, simple bottom line.

Upside is that it can run smooth - mine's great to 80 MPH (can't recall ever thinking I needed more speed), aside from a slight ~55 zone I just avoid. I lived with it a good decade, never changes & fine to me - it's not a BMW.
 
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Squash

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Put the beast up on four jack stands with tires removed...start the engine and bring it up to speed.
If no difference remove/replace a driveshaft and repeat till you narrow down the search.
 
Joined
May 9, 2010
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Sorry for the lack of updates, I've been in the middle of moving from one state to another since May. All my tools finally make the final move this next weekend.

Sadly no definitive answer yet, but I'm much closer than before. I believe my problem was more than one issue.
  1. I did confirm my spindles were worn. Dimpling them got rid of the vibration intensity from oscilating. (For those worried about dimpling, I already have a new front axle kit in hand and will be ordering spindles as soon as the dust settles from my move).
  2. Replacing the motor and transmission mounts also greatly improved the vibrations. (I was replacing them do to age and wear and not as part of the vibration diagnosis).
Because of number 2, my thought is it could be an indicator of the u-joint(s) in the drive shaft. A vibration in the shaft could be transalated more into the body through the transmission and motor through hard mounts. This is just an assumption though. So feel free to correct me. Once the move is over, my next test will be to put the vehicle up on 4 stands.

I'll keep the thread going as soon as I get more results!
 
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Is it buzz type vibration? If so, it is most likely something drive shaft related. If it is a lower harmonic, say something along the lines of a high speed bass drum lick, you are looking at something tire related. If it varies with engine RPM, it is from the torque converter forward into the engine.

The fact that new shocks reduced the vibration would make me think tires from behind the keyboard. If the shocks are worn, the the tire isn't balanced and round, the shock may not be able to control the energy of the out of balance tire. I've seen it on other cars going down the road, with one tire literally bouncing like a ball off of the road surface.

I've had tires that balance fine, but still shake the truck silly. I found a local who does road force balancing, and he pinpointed the problem tire as being out of round. He broke the bead and reseated the tire rotated to a specific spot on the wheel, and that greatly reduced the issue. If the tires were new, I would have gotten them replaced, but as they were used, I dealt with the little bit of vibration that was left.
 
Joined
Mar 21, 2015
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I also just dealt with vibrations that were happening around 65-70mph. Sometimes it would come and go depending on the surface, but it was pretty consistent and very noticeable. It felt like I was sitting on a washing machine.

I had my wheels re-balanced and mounted to a different set of rims, but that didn't seem to help much. Recently I rotated my wheels (properly torquing them by hand) and that seem to have greatly reduce the vibrations. My shocks could use a refresh too, so I'm attributing the little remaining vibrations to that which I will be replacing soon.
 

Iceaxe

I am my rig's nemesis.
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I'm bumping this thread cause I'm having the same issue post-tough trail ride....
 

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