Strange vibration at 60 MPH and above. - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Hook'em · 05-03-2017, 03:06 PM

Quote:

Originally Posted by The Swed

It started vibrating again so I took it up to 85 mph and the tach was over 4ooo rpm and it smoothed out. Im trying to break it now so know what to fix. I may end up a stain on the wall but at my age I just don't care.

Can't help with your issues, but that there is signature worthy.

snipescastle2 · 08-14-2017, 01:14 PM

I have a similar issue with mine, it starts at 70 mph and gets worse as you accelerate. I'm almost positive it's the pinion bearing in my rear end. Although, I have heard things like accessory drive pulleys can cause this vibration as well.
Having just replaced my Harmonic balancer, belts and new Alternator, I'm leaning more towards my pinion bearings. I've bought all the required bearings,seals and crush sleeve to see if this remedys the vibration issue.
Good luck finding your gremlin!
Ben Smith

Bigdav160 · 08-14-2017, 05:05 PM

Do you have a smart phone? I know there are vibration analysis apps you can use. If we knew the frequency we can pinpoint the source easily.

snipescastle2 · 08-14-2017, 06:02 PM

I have an Iphone

huntznsam · 08-14-2017, 06:32 PM

"What's the frequency, Kenneth?"

**kwmech** · 08-14-2017, 06:39 PM

Even though they "reclocked the drive shaft" doesn't mean a thing. It could still be 180 degrees out. Pull the complete shaft out and check the u-joints for any binding or sticky spots.

**Stocker** · 08-14-2017, 08:11 PM

Quote:

Originally Posted by huntznsam

"What's the frequency, Kenneth?"

Dan Rather reference?

Bigdav160 · 08-14-2017, 08:39 PM

Vibration Diagnosis Tools - The NVH App - YouTube

toolboxchev · 08-14-2017, 10:31 PM

Here is a cheap stab at diagnosis 101. The carrier may look and feel ok but under load may make it wobble. I could not tell on mine till I had the drive shaft and bearing assembly out. Nobody is perfect.

Next, Grease all the U-joints, drive and grease again. If you have no grease fittings on them replace them with a quality part with grease fittings.

**Steeveedee** · 08-15-2017, 12:32 AM

Quote:

Originally Posted by Stocker

Dan Rather reference?

REM, not RPM.

**tdangle** · 10-13-2017, 07:26 PM

Did this ever get figured out? I have the same issue

snipescastle2 · 10-14-2017, 10:55 AM

Most of my vibrations were attributed to excessive carrier side bearing clearance,
I didn't have the side bearings shimmed tight enough. And the pinion preload wasn't sufficient as well.
Vic here on the board(crusty,rusty,leaky,squeaky) gave me a hand setting it up. He happened to have a fixture that allowed him to check my housing to ensure that it wasn't bent, after that, it went together pretty straight forward from there.
Have a good one!
Be

kileyb · 11-24-2017, 12:27 PM

That software is $400 😳

Quote:

Originally Posted by Bigdav160

Vibration Diagnosis Tools - The NVH App - YouTube

LT102 · 11-25-2017, 09:18 AM

Had similar vibration on my 71' C20. The problem was the right front shock had loosened at it's top mounting position. When it happened I had just hit 70 mph and thought I was going to die it vibrated so bad. I may be wrong but it's something to look at. it affirmed to me the importance of good, properly mounted shock absorbers.

08-14-2017, 01:14 PM	#27
snipescastle2 Registered User Join Date: Mar 2009 Location: WARRENSBURG,MISSOURI,64093 Posts: 1,518	Re: Strange vibration at 60 MPH and above. I have a similar issue with mine, it starts at 70 mph and gets worse as you accelerate. I'm almost positive it's the pinion bearing in my rear end. Although, I have heard things like accessory drive pulleys can cause this vibration as well. Having just replaced my Harmonic balancer, belts and new Alternator, I'm leaning more towards my pinion bearings. I've bought all the required bearings,seals and crush sleeve to see if this remedys the vibration issue. Good luck finding your gremlin! Ben Smith __________________ "Persistence is the twin sister of Excellence.one is a matter of quality,the other, a matter of time" “Serious Black” my 1971 Short Bed Fleetside Sold to an outstanding man in Lees Summit,Mo. “Gone, but by no means,Forgotten”

08-14-2017, 05:05 PM	#28
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Strange vibration at 60 MPH and above. Do you have a smart phone? I know there are vibration analysis apps you can use. If we knew the frequency we can pinpoint the source easily. __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

08-14-2017, 06:02 PM	#29
snipescastle2 Registered User Join Date: Mar 2009 Location: WARRENSBURG,MISSOURI,64093 Posts: 1,518	Re: Strange vibration at 60 MPH and above. I have an Iphone __________________ "Persistence is the twin sister of Excellence.one is a matter of quality,the other, a matter of time" “Serious Black” my 1971 Short Bed Fleetside Sold to an outstanding man in Lees Summit,Mo. “Gone, but by no means,Forgotten”

08-14-2017, 06:32 PM	#30
huntznsam Registered User Join Date: Jul 2017 Location: Will Co IL Posts: 30	Re: Strange vibration at 60 MPH and above. "What's the frequency, Kenneth?"

08-14-2017, 06:39 PM	#31
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,387	Re: Strange vibration at 60 MPH and above. Even though they "reclocked the drive shaft" doesn't mean a thing. It could still be 180 degrees out. Pull the complete shaft out and check the u-joints for any binding or sticky spots.

08-14-2017, 10:31 PM	#34
toolboxchev Registered User Join Date: Jul 2015 Location: 2nd left past the stump on a dirt road. Posts: 2,629	Re: Strange vibration at 60 MPH and above. Here is a cheap stab at diagnosis 101. The carrier may look and feel ok but under load may make it wobble. I could not tell on mine till I had the drive shaft and bearing assembly out. Nobody is perfect. Next, Grease all the U-joints, drive and grease again. If you have no grease fittings on them replace them with a quality part with grease fittings.

10-13-2017, 07:26 PM	#36
tdangle Senior Member Join Date: Mar 2005 Location: Jurupa Valley, Ca Posts: 1,209	Re: Strange vibration at 60 MPH and above. Did this ever get figured out? I have the same issue __________________ Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC

10-14-2017, 10:55 AM	#37
snipescastle2 Registered User Join Date: Mar 2009 Location: WARRENSBURG,MISSOURI,64093 Posts: 1,518	Re: Strange vibration at 60 MPH and above. Most of my vibrations were attributed to excessive carrier side bearing clearance, I didn't have the side bearings shimmed tight enough. And the pinion preload wasn't sufficient as well. Vic here on the board(crusty,rusty,leaky,squeaky) gave me a hand setting it up. He happened to have a fixture that allowed him to check my housing to ensure that it wasn't bent, after that, it went together pretty straight forward from there. Have a good one! Be __________________ "Persistence is the twin sister of Excellence.one is a matter of quality,the other, a matter of time" “Serious Black” my 1971 Short Bed Fleetside Sold to an outstanding man in Lees Summit,Mo. “Gone, but by no means,Forgotten”

11-25-2017, 09:18 AM	#39
LT102 Registered User Join Date: Oct 2012 Location: Greenville, Oh Posts: 72	Re: Strange vibration at 60 MPH and above. Had similar vibration on my 71' C20. The problem was the right front shock had loosened at it's top mounting position. When it happened I had just hit 70 mph and thought I was going to die it vibrated so bad. I may be wrong but it's something to look at. it affirmed to me the importance of good, properly mounted shock absorbers.



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