Vibration diagnostics

Anyone have a good diagnostic flow chart for diagnosing vibrations?

2012 Kenworth T660, 2010EPA paccar. 455/55R22.5 super single drives, 11R22.5 steer. Micheline xline

Vibration is worst when Bob trailing at 55mph. Almost feels like the front end wants to jump ou shop more then vibrate. Makes the steering wheel shake but really feels more like it's in the front end more then the steering wheel. Don't feel it in seat or feet other then whole truck is shaking you know. Driver side steer tire has wavey and excessive wear on outside trail bar only, no noticable bad wear on any other tires. Once in a while (might be in my head) it almost feels like the truck wants to wag side to side at full speed. Vibration is related to road speed, drive train stopp doesn't appear to affect it. It's hard to tell but vibration might be present at show speeds (very light it it is). Vibration really starts around 45, bad at 55 and mellows out around 60. Fully loaded (shotgun tanker) slight vibration at 70.

New steers in November, new driver at the of March. Balance beads in all tires. 3 able alignment in December. Noticed vibration in April, might be slowly progressing. Balanced steers on machine about a week ago, checked steer drums and found them round. King pins are right, no noticable slop in steer hubs. Spring bushings are worn but do not appear bad, front end appears tight (new tie rod with 3 axle assignmen). Bussing at drea link/Pittman arm may be worn, light clink in gearbox when shaking steering wheel with truck off. Drive lines and u joints feel tight, maybe a 1/16 to 1/8 of wiggle in carrier beingbe and slip joints.

Vibrations are almost as bad as electrical shorts to find for me, any help is greatly appreciated. Thank you

 

Does it seem to change at all when the steers are removed and reinstalled? I see a lot of wear on aluminum steer hubs and wheels than over time causes wheels and hubs to not run true. Look for gaps between the wheel and the stand offs on the hub. IE the hub pilot is worn. I would begin by measuring out of round and run out of steers on the truck.

I have attached the Eaton vibration flow chart for you.

 

No change remounting steers. I'm going to try to find a socket to be able to remove wheels myself this weekend so i can try getting inside it all. I'll double check this one later when i shut down. Thank you

 

I can't believe how hard it is to zero in on the little things on a big truck....

 

It's ridiculous isn't it...

 

I will tell you this!! I chased and chased and chased...and in the chase I fixed and or verified perfection everywhere. I had it feeling good but not like when I brought it home.

Now hand to God I ran Lucas for about 1200 gallons of fuel and it did more than changing my motor mounts.

In fact I think it does everything it says it does and I think a rough running big diesel motor translates to the first and worst vibration a driver starts to feel. Other ones are easier to figure out.....sloppy injector spray is not easy to figure out! But once you know you won't fuel without Lucas again!

 

Had a tire shop remove all balance beads from tires and static balance on their machine. Still getting vibration with empty and loaded trailer but it memig be a little softer now, it's hard to tell but not gone yet anyways. I'll know how much change after i get to run bobtail again.

 

Looks like you covered quite a few possibilities.

Did you check that the driveline is phased correctly (ie the trunion ends on the 4 crosses should be lined up on each driveline)?

Brake drums/rotors? They spin with the tires too. Out of balance and they can cause hop too.

 

If you have narrowed down to steer tires, see if you can find someone with beeline equipment to have them spun on the truck. Easy to pick out excessive run out this way too or rule out improper mounting.

 

Yearly alignment is recommended. Also if not many miles on tires one can be out of round from new. As much as 2/32 out of round is common now. Industry standards and quality control have gone down hill on everything made.