vibration-shimmy underload

AndyCook

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I am in scotland
Apr 16, 2010
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Fitted suspension lift a month or so ago.
havent driven the truck that far until after this weekend, i have fitted winch and winch mount - now front end has settled more it was a bit high.

For first time i have taken the landcruiser on longer drivers and fast.
I have noticed a shimmy-vibration come on above 50mph

it is felt through body of car and accelerator pedal.
it only occurs when engine under load - e.g. hill climb or accelerating briskly to overtake.
the vibration eases noticeably if I lift off the accelerator

i suspect it could be a rear prop UJ (although these only had a little movement - the back one when i last checked)
since the angle of the prop will now be steeper following the lift

do these sysmptoms fit with a worn UJ?
 

24Seven

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Mar 1, 2010
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AndyCook said:
i suspect it could be a rear prop UJ (although these only had a little movement - the back one when i last checked)
since the angle of the prop will now be steeper following the lift

do these sysmptoms fit with a worn UJ?
It does sound like a worn UJ's and you should not have any "play" in the joints at all btw.
 

DaveWall

Active Member
Mar 14, 2010
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Andy - with the vibrations on the 90 series, take the practical approach,

Check the easiest first, then the obvious, before getting to involved.....

Does sound like UJ issues, I would advise packing the UJs with some decent greese first off, see if there is ANY effect on the vibration. I agree there should be NO play on the UJs (and little to None on the sliding joint)

Dave

P.s. if you do go for new UJs watch out for how they are greesed, the cheapest out there are VERY VERY difficult to greese on the vehicle (I actually swapped back to genuine UJs as I was so annoyed with trying the Milner ones (I never did get any takers on the Milner UJs I had so if you are on a tight budget your welcome to the ones I bought from Milner - you could find longer nipples and use them)
 

silvercruiser

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Mar 22, 2010
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Hello i to will be reverting back to genuine u/j's as i fitted a milner one and after 1000 miles i have play in it already and a slight vibration when letting off at 60/70mph so yes andy change the u/j's :D

Joe.
 
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AndyCook

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I am in scotland
Apr 16, 2010
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thanks for ideas.
i have struggled with milners UJ on my old 4runner, so wont be going there again - dont worry!

I had already greased the UJ a few weeks ago - when wife moaned about shaking after the lift

NB - this shimmy-vibration has only started since the 40mm suspension lift

so - i have taken practical approach this evening

1) removed rear-prop (locked centre diff) and went for a drive, the shimmy was worse than with the rear prop on!
2) put back on rear prop, and removed front and went for a drive - virtually no shimmy!

checked front UJ, no slack/wobble at all, moving freely and no binding

I have greased up the front UJ, the slip joint grease nipple had lost its valve and was a bit dry, so i put a new one on and greased it.

thing is, the front diff/transfer box are the same height offset as before the lift - so front prop angle hasnt changed since lift

only the CV joints are at a steeper angle since the lift,
so i am wondering if it is CV joint related?

camber angle of wheels look much better now, following fitting on winch, front probably about 50mm higher than it was before lift now.

would bad alignment cause a shimmy/shaking under engine load - i dont think so.

i may fit a front-diff drop to see if that helps. by reducing the CV angle.
 

AndyCook

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with both props back on this morning, on drive into work - it actually felt better today. maybe the greasing of the prop UJ has helped. the front prop slip yoke was certainly pretty dry - since the grease nipple had failed, and was allowing grease to be pumped out by the slip yoke.

the vibration is still there though under load, but most people probably wouldnt notice it now its not as bad - it is akin to drive across some rough-coarse stretch of tarmac, - hard to describe!
nothing like an unbalanced wheel shimmy
 

BlackWidow

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Mar 2, 2010
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I have the same vibration on mine since I did my lift (been over a year) and as yet I have not found what it is.

Like you said it feels like driving on rough tarmac.....my girlfreind however likes it, she says it makes her feel good :shock: :lol: and that is good news for me ;)

If I ever find out what the vibration is I will let you know.

Steve
 

AndyCook

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measured gap between front wheels at back and front,
the wheels are toe-d in, as on front the gap between wheels is 10mm smaller than rear of wheels

i will have to persuade my wife the vibration is a good thing :mrgreen:
 

AndyCook

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Today had another look under the landcruiser. i had been pulling a heavy trailer today for 10miles and the vibration was worse.

one thing i noticed, was small movement of the steering rack at the bushes - only about 1-2mm is that acceptable?
and could it cause the vibration - i can feel this vibration in steering and car body -
 

DaveWall

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Mar 14, 2010
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Out of interest is there ANY play on the CV 'cups' that hold the CV joint and enter the front diff - another member on here had a vibration and play between the shafts and the front diff...

I've lifted mine, and cant say I get a vibration like driving on rough tarmac...??? If your ever near Devizes in Wilts (perhaps the Plain) give me a shout and you can try mine, see if its any different (compare bits - ooh urrr)

Dave
 

AndyCook

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Well replaced a front prop UJ - transfer box end.

hasn't solved the vibration
and have "borrowed" a front diff drop kit off Chris, to drop the front diff down and lessen drive-shaft/CV angles

- this doesn't appear to have solved the issue either....i will try a longer drive tomorrow to be sure.

Now, when i was driving on a rough track yesterday, i did notice something i haven't noticed before when driving this track.
I could feel a knocking feedback in the steering as i went over the rough ground.

jacked the front of the car up tonight, passenger side of wheel side-side - nothing untoward.
but when i do same to the drivers side there is a definite solid clonking/knocking, it seems to be coming from the steering rack. around about below where the steering wheel shaft enters it. I cannot pinpoint it.
the knock it is travelling into chassis too. the outer track rod end seems ok, i cant feel any movement in that - but can feel the knocking transmitted along it
i cant move the track rod itself - tried hauling on that.

guess it could be the inner track rod end? its hidden in the rack gaiter, i clamped hold of that, and push-pulled tyre, but couldnt really feel much - need to get a helper to wiggle the wheel whilst i listen and feel.

now if this is the cause
a) i am suprised it is more of an issue when engine under load - hill/acceleration ?
b) it seemed less severe when front-prop was removed

any ideas wise ones!?
 

Chris

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There is a joint in there. Forget what it's called but it's the rack end. Slightly different each end if I recall. I looked at that once thinking that there was play. The track rods were fine, I replaced one when i sold LB to Tony as I have stuffed up the gaiter. I wondered about the free play, but oddly it didn't seem to be there with the engine running and the steering 'powered' up. Only when static and moved by hand. I couldn't work it out. There was no play in the steering that I could detect. I certainly had no wobble anywhere nor vibration. It does sound as though it's linked to your lift.

Chris
 

AndyCook

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I will try again with engine running to see if it is noticeable,
looked on milners and they have "inner track rod ends" listed.

surprised a loose inner track rod end would cause vibration in the body/chassis of the car, i can feel it in steering too, but more noticeable in the body of the car.

i will try splitting the out track rod end first, and slide the rack gaiter over to one side and see if i can pinpoint any play in the track rod end before ordering any new parts.

the actual steering rack seems seems to have some form of preload adjustment too. - according to max-ellery manual.
there are bearings too in there, but whole rack needs replacing if they are gone.

the track rods do end up at a steeper angle after a lift, since the steering rack moves up relative to the hub attachment point of the outer tie-rod.
 

AndyCook

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Well - fixed the steering rack "klonk"

with help of neighbor wiggling wheel side-side, I ruled out the track-rod ends being loose.
definitely a klonk in the rack itself.

So i thought to try adjusting the preload spring on the rack, i only had to tighten it a tiny amount to get rid of the "klonk" - caused by slack.

went for a drive and in field, and didnt get the "klonk" feedback in steering..

so thats fixed!

BUT shimmy/vibration of whole truck still there.......
 

AndyCook

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still working on the problem

noticed it gets worse briefly when driving over crests on a hilly road, not bumps but hill-crests
the suspension will be rising even further i guess when this happens, and prop yokes stretching
 

AndyCook

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Took front prop off for a couple days: problem gone!

greased the UJ again, and the slip yoke. took the slip yoke apart to grease it, and took grease nipple off when putting back together so it wasn't too full of grease and unable to compress. put it back 180deg out, to see if that made any difference. The new UJ has play... got another on order from milners. i did knock last one in with socket and hammer. will press new one in with big vice....

put front prop back on and vibes are back! - seem worse than before.

even considering removing lift springs at front if new UJ doesn't fix this..... or getting front prop rebalanced if that is possible in Aberdeenshire

driving me mad!
 

silvercruiser

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Mar 22, 2010
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If it was me id be contacting Mr rubie and ordering a genuine UJ as my milner one had vibes and play in within 500 miles. so i fitted genuine and all is good.


Joe
 

BobMurphy

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Mar 1, 2010
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Andy,

What are the bearings on the front output shaft in the Transfer Box like ??

Is there any play in the output Companion Flange ??

I replaced the bearings in mine as a precaution but they didn't really need it so I wouldn't expect yours to be worn.

Just a thought.

Bob.
 

AndyCook

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Hi Bob

Those bearings seem OK, i have shaken and hauled up-down and side-side on the companion flange on front diff and transfer box, they don't move
there is a barely detectable in-out movement on the transfer output flange.



with the front prop on the steering is a bit heavier, but i guess this is normal. on my last 4runner, when i fitted freewheeling hubs and unlocked them the steering was lighter, than when locked.

I also noticed when cruising at say 40mph, and you release the throttle, then quickly press down on it again - there is a slight thud in the drivetrain/transmission
I don't get this when the front PROP is off

- there seems to be a bit of slack when you turn/rotate the transfer companion flange before you meet resistance- in the "chain" inside I guess - like i have found in diffs on cars I have owned, a bit of slack/lash

maybe i will get proper UJ in the future, will try the cheapo ones for now they have been ordered

I cannot get my head round why any problems with the front prop would get worse after a lift, but could be co-incidence.
and a front diff-drop didn't solve the problem either.

there is definite slack in the REAR prop UJ too, at rear diff end. but that doesnt cause any vibes when the FRONT prop is removed.

steering system fine, all track rod ends, rack bushes fine

I also cant see how a wheel balance problem or ball-joint at front end could be the problem if it goes when front prop is removed, surely the problem would still be there.

very irritating!
 
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