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Vibration when accelerating from stop [message #324298] Sun, 24 September 2017 08:56 Go to next message
RF_Burns is currently offline  RF_Burns   Canada
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Hi All,
When I accelerate from a stop, I feel a definite vibration for the first few seconds. I can't tell if it disappears right when it shifts to second because that shift is so subtle. I feel it more through the seat than through the steering wheel.

Its not an irregular vibration, but a smooth vibration that fades out. Coming back from the GMCMI rally I was in some crawling stop and go traffic. It only seemed to occur if I came to a stop.

Any ideas? First gear clutch slipping?

Thanks,


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: Vibration when accelerating from stop [message #324299 is a reply to message #324298] Sun, 24 September 2017 09:15 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Ooh. That's a scary diagnosis. Go to a parking lot and try taking off from stop with wheel cut one way and the other. Get under and check 3 support bolts on ling shaft bracket. Check for missing inner cap screws by joinys to hubs.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: Vibration when accelerating from stop [message #324300 is a reply to message #324298] Sun, 24 September 2017 09:17 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Joints. And of course recheck Dexron level. If marginal try adding a pint as a test.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: [GMCnet] Vibration when accelerating from stop [message #324306 is a reply to message #324300] Sun, 24 September 2017 09:52 Go to previous messageGo to next message
Richard Denney is currently offline  Richard Denney   United States
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And check the half-shaft bolts. If they are loose, replace them.

Rick "easy stuff first" Denney

On Sun, Sep 24, 2017 at 10:18 AM John R. Lebetski
wrote:

> Joints. And of course recheck Dexron level. If marginal try adding a pint
> as a test.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
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--
Rick Denney
73 x-Glacier 230 "Jaws"
Off-list email to rick at rickdenney dot com
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Re: [GMCnet] Vibration when accelerating from stop [message #324307 is a reply to message #324298] Sun, 24 September 2017 10:23 Go to previous messageGo to next message
Luke Walling is currently offline  Luke Walling   United States
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Rev it up at idle, does it still do it. The Eleganza I picked up started “shuddering” it felt like on my transport trip back. Seems to be the exhaust resonating in my case, thankfully.

I have tons of other stuff to fix on this one if I am to use it!

_____________________________
From: Bruce Hislop
Sent: Sunday, September 24, 2017 9:57 AM
Subject: [GMCnet] Vibration when accelerating from stop
To:


Hi All,
When I accelerate from a stop, I feel a definite vibration for the first few seconds. I can't tell if it disappears right when it shifts to second
because that shift is so subtle. I feel it more through the seat than through the steering wheel.

Its not an irregular vibration, but a smooth vibration that fades out. Coming back from the GMCMI rally I was in some crawling stop and go traffic.
It only seemed to occur if I came to a stop.

Any ideas? First gear clutch slipping?

Thanks,
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
Hubler 1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

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Re: [GMCnet] Vibration when accelerating from stop [message #324312 is a reply to message #324307] Sun, 24 September 2017 16:46 Go to previous messageGo to next message
hal kading is currently offline  hal kading   United States
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Bruce,

Balance beads or powder in the tires will do that.

Hal Kading 78 Buskirk Las Cruces NM
Re: [GMCnet] Vibration when accelerating from stop [message #324360 is a reply to message #324312] Mon, 25 September 2017 17:45 Go to previous messageGo to next message
Hal StClair   United States
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Check the bolts on your front hubs, the 4 that go in from the back side into the bearing assembly on the one ton. You can get to them without even jacking the coach up. You may have to move the wheels back and fourth to get to them all. Loose bolts here will cause just what you're describing.
Hal


"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane." 1977 Royale 101348, 1977 Royale 101586, Diesel powered, 1974 Eagle Bus 45',w/slideout, Rio Rancho, NM
Re: Vibration when accelerating from stop [message #324666 is a reply to message #324298] Sat, 07 October 2017 07:17 Go to previous messageGo to next message
RF_Burns is currently offline  RF_Burns   Canada
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I have beads in the wheels and that vibration occurs once I'm rolling at about 35-40mph and is gone in short order. This starts the moment I press on the gas. Its a fast vibration, so it maybe engine related. Its a smooth vibration, not sharp. It disappears once I get rolling and the engine RPM is above 2000.

My engine always seems to run rough when I rev the engine from idle, so it maybe related to that.

To try to cure that I have changed the coil and pickup to be sure I have proper phased ones (from DickP), new distributor cap, new rotor, new module, 2 sets of spark plugs (AC #7 and now NKG), 2 sets of DickP's plug wires (I pulled the spark plug connector off the wire on a couple trying to remove the wire from the plug)

One time I tried shorting out each plug in turn by removing the plug wires from the cap and looping a small copper wire around the terminal, then replacing the wires on the cap. I was able to cut the spark to each cylinder, but I was not able to determine that any one cylinder was the cause, they were all firing. I gave up thinking it was just the nature of the beast

We are taking it to the family cottage about 30 miles away today, so I'll try to pay more attention to symptoms.


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: Vibration when accelerating from stop [message #324669 is a reply to message #324298] Sat, 07 October 2017 09:47 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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If you suspect a light part throttle transitional engine miss, have someone do very light "brake torque" moves from idle to light part throttle in D in the suspect range. You listen and feel with your hand at tailpipe for miss. Simple quick test to isolate if engine miss or drive train harmonic vibration. Could be gummed pullover slots in Qjet or any number of things like plug gap wrong. If no miss, move your diagnostic efforts to rotating drive train assembly parts.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: Vibration when accelerating from stop [message #324670 is a reply to message #324298] Sat, 07 October 2017 10:29 Go to previous messageGo to next message
Scott Nutter is currently offline  Scott Nutter   United States
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Seems like there was a discussion on a similar situation a few months ago. If memory serves, I think the problem was the u-joint in the half shaft.
Good luck.


Scott Nutter 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI Houston, Texas
Re: [GMCnet] Vibration when accelerating from stop [message #324673 is a reply to message #324670] Sat, 07 October 2017 10:42 Go to previous messageGo to next message
James Hupy is currently offline  James Hupy   United States
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Bruce, check the inboard cv on the drivers side of the coach. The 12 point
bolts thar secure the joint to the final drive flange are know to loosen
and cause the exact symptoms you describe. If they are loose, remove them,
wire wheel the threads, de-grease the internal threads with brake-kleen or
similar, and use blue loctite and retorque them to 55 foot pounds torque.
While you are under there, check your boots for tears. Check the half shaft
carrier bearing on the passenger side as well.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

On Oct 7, 2017 8:29 AM, "Scott Nutter" wrote:

> Seems like there was a discussion on a similar situation a few months ago.
> If memory serves, I think the problem was the u-joint in the half shaft.
> Good luck.
> --
> Scott Nutter
> 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final
> drive, Quad bags, tankless water heater, everything Lenzi.
> Houston, Texas
>
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Re: Vibration when accelerating from stop [message #324767 is a reply to message #324298] Mon, 09 October 2017 20:44 Go to previous messageGo to next message
RF_Burns is currently offline  RF_Burns   Canada
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So I payed extra attention to the "smooth vibration" I felt while accelerating from stop and it didn't do it this weekend! it was only about 100kms so not a long trip and all highway.

Today I decided to go into town and dump the black tank. I wasn't thinking about the vibration and then I felt it! So after a few in-town stop lights and some testing, it appears it happens when the engine is about 1800rpm. Doesn't matter if I'm accelerating or steady state or decelerating, or any particular speed, at around 1800 RPM there is a vibration. So either an engine in-balance or a resonance at that RPM. May also be related to the rough engine I feel if I rev the engine.


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Re: Vibration when accelerating from stop [message #324771 is a reply to message #324298] Mon, 09 October 2017 21:47 Go to previous messageGo to next message
JohnL455 is currently offline  JohnL455   United States
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Could the balancer have spun or shifted on rubber? Common Olds issue with age. When it happens try in neutral to rev above and below to rule out drivetrain.

John Lebetski
Woodstock, IL
77 Eleganza II
Re: Vibration when accelerating from stop [message #324772 is a reply to message #324298] Mon, 09 October 2017 21:48 Go to previous messageGo to next message
Scott Nutter is currently offline  Scott Nutter   United States
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Do you also get that vibration when parked but with throttle at 1800 rpm's?
I don't think it's the engine.


Scott Nutter 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI Houston, Texas
Re: [GMCnet] Vibration when accelerating from stop [message #324778 is a reply to message #324772] Tue, 10 October 2017 01:01 Go to previous message
johnd01 is currently offline  johnd01   United States
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I had a problem like that on my Park Avenue. Turned out to be a tire
tread delaminating from the tire casing. The tread was slipping on the
casing. You would think that would be very visible but it was not. It only
happened while accelerating from a stop or very slow speed. After about
25MPH the systems went away. It finally got bad enough that I saw the line
between the cap and casing. I had done a brake job hoping that would help.
It did not. Then I changed the rotors, still no help.

On Mon, Oct 9, 2017 at 7:48 PM, Scott Nutter wrote:

> Do you also get that vibration when parked but with throttle at 1800 rpm's?
> I don't think it's the engine.
> --
> Scott Nutter
> 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final
> drive, Quad bags, tankless water heater, everything Lenzi.
> Houston, Texas
>
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> Unsubscribe or Change List Options:
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*John Phillips*
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Johnd01 John Phillips Avion A2600 TZE064V101164 Rancho Cordova, CA (Sacramento)
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