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Re: 5KCST Harmonic vibration-help

> From:          Richard Walters <sierrar@sagedb.minden.nv.us>
> Subject:       5KCST Harmonic vibration-help

> I would appreciate any advice on a problem affecting both of my 1986
> 5KCST's, one 5-speed, one automatic.
> After both cars had their tranaxles out (for clutch, and differential
> repairs, respectively) they both now have a vibration/harmonic rumble,
> which seems to be coming from the exhaust system. The vibration/noise is
> most noticeable at 1800 and 2900 RPM's (both cars.)
> Were the catalytics or mufflers affected during the manifold removal?
> Could the internal baffles have been damaged? Is it simply the rubber
> mounts that need adjustment?


        I kind of laughed when I first read this as I too was going to post the
list for the exact same problem as you. My '87 5k Tq recently had both 
motor mounts replaced but none of the exhaust was moved in doing this
repair. Everything seemed fine and then about a week later I noticed that
at exactly 1800 rpm, there is a harmonic vibration that came about. Thought
it was the Catalytic converter shield as this has worked itself loose before 
but the shield is very tight. I've poked and prodded around under the car
and checked all the exhaust for rubbing points and have found nothing. I am
totally stumped on this one. Also, it can't be the cat inards because, well, umm
they took a hike. One more point, the vibration does not yield itself while
the car is stationary. You must be moving with the tach sweeping past 1800
rpm. Noise is gone by 2000 rpm. ????????????? Any BTDT? Thanks,

Chad Clark '87 5k Tq  -lovely noises :(