Driveline Vibration. U-Joints, Carrier Bearing, and Output shaft Bushing Replaced.

[RedBarnLLC]

In my 1985 C10 I've got a pretty good vibration throughout the truck that I can't quite nail down. As stated in the title, I've replaced the carrier bearing, all 3 U joints in the 2-Piece driveshaft as well as the output shaft bushing in the tailshaft of the transmission. The Tires have all been replaced and balanced yesterday which seemed to help some but still a noticeable vibration at any speed above 35 MPH or so. The U joints are in phase, but I suppose it could be 180 degrees out? I will try that first and if that doesn't fix it then I will take the drive shaft to get balanced. The pinion bearing seems nice and tight with no noticeable play. Looking for some other opinions if there's something I've overlooked!

Thanks. I'll Include some pictures of the truck.

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[Dutch Rutter]

Is check out motor and trans mounts. As well as the rear leaf spring bushings. An alignment might also help.

 

[1987 GMC Jimmy]

I’m assuming you’ve checked for play in the steering and ball joints. It seems like you’re very thorough, but if you don’t ask, you don’t know.

 

[Kim Burke]

A dent in the drive shaft? Counter weight fall off?

Did the vibration get better, worse, or no change after the aforementioned parts were replaced?

Did you lower the rear, by chance?

 

[Kim Burke]

Vibration is from something spinning. Get up to speed and unload the drivetrain by kicking it into neutral. Rev the motor and see if the vibration is constant or changes with rpm. That will rule out one or the other.
I just went through this. Should have left my OE wheels on the damn thing.

 

[RedBarnLLC]

All stock height suspension components both front and rear. It seems the vibration is a little less severe after all the parts have been replaced. Shifting to neutral does not eliminate the vibrations. I think I'll be balancing the driveshaft after I rotate the two pieces 180 degrees to see if the factory balancing is just 180 out.

 

[RedBarnLLC]

Steering joints, Ball Joints and motor/trans mounts are all solid. Thanks for the advice though. It feels like its a driveline vibration more than from the front suspension.

 

[PrairieDrifter]

The stuff mentioned above and then wheel bearings as well.

 

[eskimomann209]

Rim size?
I had someone put new tires on my truck and the 15s were balanced with theirs stuck on weights ...
My calipers ripped them off...
Then one of my other trucks I got an out of round tire right from the tire shop

 

[bedwards]

I had a vibration in a vintage car that I traced down to the torque converter bolted to the flywheel in the wrong place. There are markings where they should mate up and its not hard to check it, just drop the cover.

 

[Nonstop]

Might have missed it, but have you rotated tires to see if the vibration moves?

 

[Oldsnut]

I've been chasing a similar vibration for years, but I would suggest removing the rear section of driveshaft and checking to see if the vibration is still there. Mine is and I assume this means it is transmission or torque converter or as bedwards above mentioned the mating of flywheel and TC. This would at least give you some direction. Good luck, I hope you find what is wrong.

 

[RedBarnLLC]

I appreciate the help. I have not tired rotating the tires but this problem persisted before the new tires, and after as well. I will get a chance hopefully today to re-index the driveshaft and I will report my findings.

 

[JScottGladden]

I’d get the shaft balanced as you mentioned. That worked quite well for me once, and you may find yours to be slightly twisted.

 

[Rusty Nail]

We're gonna need some new pix the way this thread is carrying on like this...

but this problem persisted before the new tires, and after as well

Looking back to BEFORE the tires..there was a change of some kind.
It appears you do good looking work and are at MANY parts of your '85, but what were you doing / what happened that STARTED the vibration? Or what caused you to notice it?
This isn't a truck you just bought, think back to the time when there was no vibration. THEN what happened OR what did YOU do to it?