marko69

I have a vibration around 76mph, vibration for about 3 seconds, then calm for 3 seconds, vibration 3sec, calm for 3 sec.....and it just continuously cycles like that. I have new front tires. Took it to the dealer for an alignment and wheel balance and that cured about 70% of it. It's still there but not as pronounced. Had the same problem on a Cadillac Catera, tried new tie rods but no help, new control arm bushings and ball joints cured it. Watchyall think, start with bushing 100 or should I be looking elsewhere?

perren75

Had similar issues last year...

First i changed tranny-mount (rather cheap and it´s an straight forward easy job - took max an hour).. That removed perhaps 50% of the vibration..

Then a month later i got it aligned and put on new tires w./ balancing.. Took care of the rest - rides real smooth after that..

So what´s the status of your tranny-mount? Has it been changed? Mine was totally worn out.. 12000km / 12 years.. Don´t think it´s been changed before.

Best regards,
Pelle

marko69

I changed the transmission mount a couple of weeks ago, that did clear another nasty vibration I was having.

perren75

Ok...

So now i´m down to guessing - what about engine mounts? I´ve read quite a bit about them causing vibration but mostly on specific RPM´s - not speed..

My transmission mount caused vibration mostly between 2000-2500rpm.. Unbalanced wheels above ~120km/h (65Mph??)..

Could the wheel balance be just a bit off still? (Did you watch them do it? One time I´ve been unlucky balancing wheels and it was far from perfect and when redone it was 100% perfect). Seems like the ABC chassi tends to cycle the vibrations when wheels are unbalanced). Could there be anything on the brake-discs causing wheel not to align completly to disc? Before balancing and alignment the vibration was very noticeable when going +120km/h - but not at all in lower speed.

I had a tiny vibration left before my ABC havoc in june and after changing pump, all accumulators, pressureline etc there seems to be absolutly no vibration at all.. Recon that might have been the pulsation dampener but could not tell as everything were replaced at the same time due to "ABC Visit Workshop" in red on the dash. 40hours of labour.. pheew.. And around $2000 in parts.. All done on jackstands at home..

As said - just guessing.. And from previuos cars that had faults in bushings etc. there were "clunking" noises when driving slow - not just vibration when going on the highway..

Best regards,
Pelle

JaySee56

Have you had a look at the driveshaft flex-disks? That may have caused your transmission mount problem also.

kbob999

The on/off rhythm sounds like tires or wheels. If they are slightly out of balance, they are sometimes in phase, and 1000 feet later out of phase. Could be side to side, or front to back.

Do you have wheel spacers? If so, remove them and test again. What about aftermarket wheels? Non hub centric spacers or wheels will cause this issue. I had this imbalance with my snow wheels and fixed it with hub centric rings from Tire Rack.

Heatwave

You mention that your front tires are new. What about the rear tires? As the rear tires wear down closer to the treadwear indicators, they get increasingly noisy. I know that our tires are supposed to be unidirectional, but as a cheap and easy method for isolating your noise, you might try swapping the rear tires just to see if that affects the sounds you are hearing. It might be that you need new tires on the rear. Doesn't cost anything to try. Good luck, Mate.

marko69

Ok guys,
I'll have a look at some of ya'lls suggestions and let you know what I find.

SLcharge

I had somewhat the same issue.
Cyclic vibrations, starting at 60 mph, 2 sec on 2 sec off. At higher speed it went on, the cyclic time increased, but not the amplitude.
Nothing to feel in the steering wheel, only in the chassis, seat, the pedals, etc.
It turned out to be the front wheel hub bearings, having a slight play, and no pretension.
After replacing them, the vibrations was gone, and have not returned.