Mystery Vibration

nissan
vibration
quest

#1

Our '02 Nissan Quest minivan has a vibration that none of our mechanics can figure out. It is speed related, making us believe it has to do with one of the drive or suspension parts, but none of the following actions has helped:

Balance 4 wheels

Rotate tires

4-wheel alignment

Replace half-shaft (bad CV boot)



The vibration is worst at about 58-63 MPH, and smooths out somewhat above that. Also, it is much worse in a slow LEFT turn, and much BETTER when we take a slow RIGHT. (Again, suggesting something in the suspension…) It is absent (according to the mechanics) when the car is running on the lift (therefore unloaded).



Does ANYONE have any clues or experience with this kind of problem? It seems to be getting worse as time goes on, but the car only has 65k miles and we’d like to get another 2 or 3 years out of it. Thanks!


#2

I’d start suspecting the front wheel bearings.

Tester


#3

Just a tought but what about the rack and pinnion steering assy. I take it that they checked all the inner and outer tie rods and all ball joints.


#4

when did this vibe start? both time wise, and mechanical repair wise?

you mention turning. how fast are you going when turning, at the noted worse left than right?

when was the last brake job? have the wheel bearings been replaced?

get up to speed on the interstate (in safe traffic conditions) when it is above the 63 threshhold, put the gearshift in Neutral. coast all the way down to 30 (again, make sure there is not much, or NO trffic to worry about) see if there is a difference in vibration. if the noise goes away, then it may be transmission related. but if it is still there with the trans in neutral, then it is in the drive train, or suspension. if you have the space, or in a parking lot do this, while turning. get up to speed (safe for a parking lot!) and put it in neutral and see if it makes any difference either way.

how many miles on the tires?


#5

Wheel bearings have been checked, apparently ok.
Yes, I believe the ball joints and and tie rods have all been inspected.
I’m doubtful that anything in the rack & pinion would be it, because why would that cause a speed-sensitive vibration with no steering input?

We first noticed this when the car was new. The dealer originally thought it was a bent half-shaft and replaced it. Seemed to help, but as I noted, the problem has been there to a small (barely noticable) degree from the start. It HAS gotten progressively worse and is now to a point that we’ve gotta figure it out. The problem when turning is noticable at any speed, at parking lot speed (10 mph) we can tell that the farther you turn left, the worse it is, and vice versa. Don’t recall mileage at the last brake job, but wheel bearings were checked out ok at that time. Tires were new at 50k miles.

Thanks to all for your thoughts!


#6

Sorry, anything more? Anyone??


#7

Just a guess, but the fact that it happens while turning one direction makes my suspect a CV joint. Did they only replace one half-shaft?


#8

I believe so, yes. I’ll have to double-check the invoice.


#9

to try to figure out if it is transmission related, or drive train related:

get up to speed on the interstate (in safe traffic conditions) when it is above the 63 threshhold, put the gearshift in Neutral. coast all the way down to 30 (again, make sure there is not much, or NO trffic to worry about) see if there is a difference in vibration. if the noise goes away, then it may be transmission related. but if it is still there with the trans in neutral, then it is in the drive train, or suspension. if you have the space, or in a parking lot do this, while turning. get up to speed (safe for a parking lot!) and put it in neutral and see if it makes any difference either way.


#10

Even though you rotated the tires, you still might have a bad tire or bent rim. If you could arrange it, have four known good tires mounted on known good wheels installed and see how the vibration is affected. If this is not feasible try rotating the tires side to side and see if the vibration now appears worse on slow RIGHT turns. Since tire rotation is usually done front to back, switching sides might be a diagnostic step.

Hope I have not suggested the obvious and have been able to help.


#11

check the motor mounts for sag and settling,also check the antiroll mounts,i only say this because you mentioned a change when turning,and at highway speeds the axles are spinning at high rate of speed which will then transfer through mounts and on to the rest of the vehicle resonance.good luck