Vibratioin at 30psi and around 1300 rpm

[DKenworth]

So did you fix vibration? If not, if you have jack, jack it up front tires, and check them, one of them could be out of round, and couse vibration to whole truck!

[in2trux]

(05-09-2017 )Trucker66 Wrote:  

(05-01-2017 )Shotgun74 Wrote:  Trucker66 did you get your vibration problem solved?

Not yet, I hope to get home this weekend and get the hanger bushing and see if that helps. As soon as I do I'll update this and let you know if that was the issue or not.

Make sure you get a NEW pinion nut if you're replacing the carrier bearing, one time use, they stretch. I replaced ours, the bearing was cocked slightly and not true perpendicular. The rubber fatigues and it can get past the most experienced hands.

Check your ride height. Leveler valve riding a little high or low will throw the drive angle enough to cause vibration.

Play in U joints is rotational gear lash, not side to side or up and down. They should be tight,no play.
Do you grease the truck yourself? I've found zerks that wouldn't take grease on "fleet maintained" trucks, they just dab a little on them to look like it was greased.
Your best friend,
https://amzn.to/2Vi6r7j
Know that it's done right.

I make sure each cup pushes out old black grease until I see color, wipe and remove excess.
Any build up of grease and dirt can throw balance of drive shaft. Don't think you have enough miles for the slip joint to be worn.

This may sound anal but any build up of dirt on the inner rims can throw tire balance enough to cause ghost vibration. A set of Centramatic dynamic balancers are well worth the price to high speed balance tires,rims and drums. It only takes one that's out to keep you chasing that ghost vibration.
Just a few things I've learned to keep from pulling my hair out and throwing money out the window.

P.S. 30 psi boost @1300 rpm is lugging too low, drop a gear and keep it @ 16-1700. It will pull better, you'll drop your boost to 20 and get better mpg. Try it.

[Trucker66]

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P.S. 30 psi boost @1300 rpm is lugging too low, drop a gear and keep it @ 16-1700. It will pull better, you'll drop your boost to 20 and get better mpg. Try it.
[/quote]
That's pretty much what I've been doing.

As soon as I figure it out I'll update this....I'm going to replace that that carrier bearing and if that dont fix it, I'm going to put the HP and torque back to where it was.