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hhow55 · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

what about having truck tested on a dynamometer?

Chamberpains · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

Thats a terrific idea hhow55. Thank you. I should've put that in my post as an alternative or a first resort.
A dyno is great and safer if you have access to one. Plus you can chain them tight to put pressure on the wheels like there is a load on. It would probably find his noise faster. If the dyno shop lets him climb all over the truck while its in motion. I would go this route if you have access to one. I never had access to one when I was a wrench.

Rawze · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

Do a cylinder cut-out test on the engine at idle, running it on one cylinder at a time and see if the noise appears. If it is a spacer or something in the tranny, clutch, etc. It will show up.

No noise = it is likely past the tranny.

alborz · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

Thank you friends for your inputs
The noise appeared just after three axle alignment and bushing change
So the tranny can not be the source of creating noise

Chamberpains · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

Well then, the only thing they do when they perform alignments is put shims in around the torsion bars or the trailing arms and spring mounts. You can always go around and check all your bolts and springs and torsion bars for proper mounting. Maybe they tightened one up out of whack and it's touching metal on metal. Also you can loosen them up and tighten them back down to make sure they're properly torqued. If any of these are your problem your alignments going to be out of whack to fix it anyway. I imagine if a spring is touching directly to the hanger you may pick up some road noise traveling through the hanger into the frame rail and back up into the cab.

Hammerhead · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

(02-08-2018 )Chamberpains Wrote: THE FOLLOWING IDEA IS VERY DANGEROUS AND CAN CAUSE HORRIBLE DAMAGE IF DONE IMPROPER!!
...
USE AT YOUR OWN RISK. THIS METHOD IS VERY DANGEROUS!!

I've had great success using this method to find those hard to find noises or shimy and shakes at certain speeds drivers complain of.

The most important step in this procedure is...

DON'T FORGET TO OPEN THE SHOP DOOR!!!
and to have a calm, cool, collected guy in the drivers seat in case of Holy shi#t moment...
Unless you require a torque load to reproduce the noise, this is a very inexpensive effective way to find the source of an issue.

Oh yeah, and don't be stupid and stand behind a truck while doing this, because it will throw the little stones stuck in the tires...VERY HARD! Don't be a target.

kryten · 02-08-2018, **(Subject: Drive line noise mystery? Solved )**

(02-08-2018 )Hammerhead Wrote: Oh yeah, and don't be stupid and stand behind a truck while doing this

Hammerhead - That reminded me of this little tidbit from Top Gear. Jezza gets it in the plums.

Chamberpains · 02-09-2018, **(Subject: Drive line noise mystery? Solved )**

Hahaha, that's terrific kryten! Me plums, oh me plums! I love that show. I'm glad they got back together on the new show "The Grand Tour"

Thanks Hammerhead the crash test dummy in the drivers seat had better be quick reacting. Or pick a spot to do it where the run away ramp ends somewhere safe and cheap to recover the truck. I used to do this by myself with a lot of extra time securing jack and frame stands. It's amazing how fast you can find that 1 drive tire thats mis-mounted or out of round just by watching the tires spin or that drive shaft that has a slight wobble to it.

Rawze · 02-09-2018, **(Subject: Drive line noise mystery? Solved )**

(02-09-2018 )Chamberpains Wrote: Hahaha, that's terrific kryten! Me plums, oh me plums! I love that show. I'm glad they got back together on the new show "The Grand Tour"

Thanks Hammerhead the crash test dummy in the drivers seat had better be quick reacting. Or pick a spot to do it where the run away ramp ends somewhere safe and cheap to recover the truck. I used to do this by myself with a lot of extra time securing jack and frame stands. It's amazing how fast you can find that 1 drive tire thats mis-mounted or out of round just by watching the tires spin or that drive shaft that has a slight wobble to it.

I have seen guys use a much easier and safer way to find vibration and drive line problems. They use a go-pro (or 2) with one of its dozens of different style mounts avail for them and some zip ties so it does not fall off. I have seen drivers do this before a few times. Looks kinda cool so see video of the underside of a truck while driving too.