Whole lotta shakin goin on...

[JCampbell1180]

Thursday night I developed a nasty little vibration that is causing me some concern. At about 30-35mph, my '77 C30 crew cab dually starts shaking like I'm doing 90mph down a washboard road. It doesn't subside with increasing speed. It will only stop if I slow to under 25mph, or so.

My initial thought was that the harmonic balancer went bad, but when I got home and checked, it was a-okay. So I just parked it until I figure out what's going on. I have a few ideas, but I want to keep them to myself so as not to suggest the problem.

So how 'bout it? Anybody have any ideas on what the culprit may be?

 

[apache]

Have you a driveline issue or possible still a tire problem? rev the engine to the RPM the vibes happen and see it happens,if no move on to U joints or slip yoke by checking by hand. Next is the steering wheel shaking like a tire problem up front. Personally Ive had more tire issues than I care to remember,lost weights,tires seperating,junk tires,the toyota hub centric or lug centric PITA.
Start isolating things and you`ll find the problem.

 

[JCampbell1180]

Yeah, I revved her up already...it's definitely in the driveline somewhere. It's not vibrating the steering wheel. I rebuilt the front suspension this summer, so I'm almost 100% certain it's not that. I did happen to have a bad front tire that I replaced Saturday. I was sure that was the problem, but alas, it changed nothing.

I'm wondering if it's the carrier bearing, though that would be more of a banging noise upon acceleration if I rely on past experiences. Looks like the OE unit, and I lowered the truck earlier this year, so I'm thinking it could be the guilty party.

It's not death wobble...it's just a vibration. Like I said, it feels like I'm driving down a washboard road.

 

[Hogback Fabrication]

Any play in the pinion or u-joints?

 

[Blue85]

Is it death wobble?

Otherwise check the stuff above

 

[Big Blzn]

My ujoint in the driveshaft went out last week at a stop light. Hit the skinny pedal on green and BOOM. Knew immediately what it was. I heard some faint squealing the day before so I got under the K5 to shake, push and pull the driveshaft to see if there was anything loose and it all seemed tight and good to go. I thought it was a ujoint going bad but thought I had till the weekend to get it replace, wrong. Less than 24 hours and 15 miles it blew at the t-case ujoint. Along with the squealing there was a pretty decent vibration as well. The moral to the story, for me anyways, your drivetrain may feel tight but I'd bet it is your ujoints ready to let loose.

 

[Thunder]

Sounds like u joints to me. Most likely have more than 1 bad. With a long drive train like yours. I would replace them all and check the carrier bearing too.

 

[JCampbell1180]

Hmm...now that you mention it, I did notice I had developed a slight squeel at various, semingly random intervals. Guess I'll be dropping that shaft this weekend.

Thanks Guys!