oamhmad

iTrader: (1)

I've been chasing a vibration issue at highway speeds for a while now and i just recently resolved it. The out come was surprising!

Like a lot of people here, my third gen would vibrate and shake pretty bad at 60 mph. I eliminated the harmonic damper, pilot bushing, flywheel and clutch. I bought an aluminum drive shaft and all that did was move the vibration up to 75 mph.

Next I eliminated a pinion angle issue by buying new stock springs for the rear and using a new stock transmission mount. Didn't change a thing.

I removed the wheels and rotors, and with the rear axle on stands watched the hubs turn at slow speed and could not notice any thing bent.

Here is where it gets interesting, with the axle on stands and no wheels and rotors the car would shake something fierce at 75 mph and the rear axle would make a high pitched screaming sound so loud I was afraid to push it any faster. So I was convinced I had a rear end issue resulting in the vibration.

Separate from this, I purchased new rims and tires and the cars is perfectly smooth nowProblem solved.

So all along I had a bent rim or two and never really knew it. I thought running the axle on stands would eliminate the wheels but I guess doing so introduces other variables that cause vibration.

Maybe it has something to do with no load on the POSI drive-train or a slightly offset pinion angle. In any case it raises the question of whether running the axle on stands is actually a valid diagnostic to eliminate bent rim related vibration issues.

Furthermore, safety aside, I'm not sure if running the axle on stands at high way speeds without the natural damping effect of the wheels and tires is a good idea.

Bottom line, if vibrations have got you dows, throw on a set of known good wheels to see if it makes a difference. Rotating tires may not make a noticeable difference as the bad rim, or two remain on the car. Also, don't trust techs at chain tire shops to balance your wheels and not notice a bent rim.

KITT1983

iTrader: (3)

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