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[GMCnet] Vibration [message #341119] Mon, 18 February 2019 13:11 Go to previous message
fbhtxak is currently offline  fbhtxak   United States
Messages: 191
Registered: April 2006
Karma:
Senior Member
John,

I, too, had an elusive vibration problem. It developed enroute to the 2016
spring GMCMI convention/Dothan, AL. At about 55MPH, a moderate vibration
would occur, resembling excessive lateral or radial wheel/tire runout.
Because of intense rain, I just stayed below 55MPH and deferred diagnosis of
the problem until arriving at Dothan and the availability of a paved parking
lot. I did find minor excessive runout at a couple of wheels, including the
RF wheel, but not really enough to explain the problem. Regardless, I
relocated them to see if there was any change... None!

Alex Ferrara noted my dilemma and recommended a visual observation of the
drivetrain at the speed where the vibration was occurring. We removed the
engine hatch, put my "cross" 2x4s in place so Alex could position himself
over the engine and then approached 55MPH on the highway. He saw nothing
alarming until about 52 MPH and then yelled "shut it down". A "balloon" was
evolving on the inside sidewall of the left front tire but would disappear
when the speed was less than 52MPH. It was one of a set of BF Goodrich
Commercial TAs, about 4 1/2 years old and about 40K miles.

I replaced the front tires at Dothan and then the rear ones upon return home
- all with BFG Commercial TAs. I didn't change brands because several other
owners (and vendors) at Dothan recommended changing tires of that
construction (polyester sidewalls/"steel" belts) at about five years,
regardless of brand. The prior tires were "all steel" Goodyear G159s. Those
things, while relatively harsh riding, lasted about 80K miles and ten years
- and yet were not worn to the wear bars when I preemptively changed them
out with the Commercial TAs. The replacement G159s were more than double the
cost of the Commercial TAs. Ten years earlier, they were only about 50% more
than tires with polyester sidewalls. Anyway, I was looking forward to the
more comfortable riding Commercial TAs - and was not disappointed.

'Look forward to the solution of your vibration problem...

Fred


Fred Hudspeth
1978 Royale (TZE 368V101335) - Tyler, TX
1982 Airstream Excella (motorhome) - Cooper Landing, Alaska





Message: 1
Date: Sun, 17 Feb 2019 18:07:36 -0700
From: John Nicholls
To: gmclist@list.gmcnet.org
Subject: Re: [GMCnet] Vibration
Message-ID:
Content-Type: text/plain; charset="utf-8"

Thanks all.
No loose bolts connecting inner cv joint to final drive, FD,. Did try to
move the joints and there was some looseness on the drivers side at the FD
but all FDs that I have touched have some movement where the axle connects.
Checked tires for out of round while having them balanced. Ride height is
low (3/8) on both sides and hace adjusted rears down also but has been like
that for years.
Would a slipped harmonic balancer affect only a specific speed range?
Removal of the axle is the next step but prior to that I am going to run a
compression test to rule out anything like a misfire although one would
expect that to be worse at idle ( I think ).
--
John Nicholls,
78 Royale w/455
Pensacola, FL


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