Loud Vibration On Turns 56 Chevy Truck
 

I have a 56 Chevy 3/4 ton long bed which I have just completed a frame off restoration. It drives good at any speed while traveling down the road. The loud vibration noise happens when the truck makes hard turns on an interstate clover leaf ramp. Any ideas about what is causing this noise would be greatly appreciated.

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Re: Loud Vibration On Turns 56 Chevy Truck
 

Stock restoration? Backing plate on brakes rubbing?
Can you post a video?

Re: Loud Vibration On Turns 56 Chevy Truck
 

posi diff possibly? when doing tight turns in a parking lot is there also a slight black mark from the inside wheel? clutch plates "stuck together in the posi, no friction additive installed with the fluid change in the diff?
tire rub
tie rod end rub on inside of wheel
without a pic or description it is hard to know

Re: Loud Vibration On Turns 56 Chevy Truck
 

All stock suspension.

Here is a YouTube link. The truck is a 4bt so it is a little noisy but you can hear the noise on the curves. https://youtu.be/znCNEVwjSF8

Here is a shot of the spindle.

Re: Loud Vibration On Turns 56 Chevy Truck
 

You need another alignment Your Tow in- tow out is slightly off
but not enough to cause wheel vibration

Re: Loud Vibration On Turns 56 Chevy Truck
 

Not being able to drive or ride in the truck makes it tougher to offer suggestions. The noise seems to be happening most often when the truck is not accelerating. It also seems to match either engine or driveline speed. And it sounds like you have a manual transmission. I would do additional testing.

1) Can you tell if the sound is coming from the front or rear of the vehicle?
2) How responsive is the steering when this is happening? Can you feel anything in the wheel?
3) If you can do it safely, try pressing clutch / shifting to neutral and shutting the engine off when the noise is happening to eliminate the engine as a source of vibration.
4) Are there any big left hand turns that you can take to see if the noise happens in both directions?
5) Do you have any links to the truck build? It may not help with the diagnosis but a 4BT Task Force truck is cool.

Re: Loud Vibration On Turns 56 Chevy Truck
 

That's a heavy noise, first I thought it might be the fan rubbing but it's heavier than that, 2nd thought is the spider gears in the diff but that's just a guess. I'd like to know when you find it.

Re: Loud Vibration On Turns 56 Chevy Truck
 

ok, stock suspension but what about the driveline?
post some under hood pics
sounds like a diesel with a standard trans, what do the engine mounts look like?what do the clearances look like around fan, manifolds, exh pipe, mufflers etc. an engine part rubbing a frame part could sound like that. it kinda uses the frame like a tuning fork.
can you have a buddy torque up the driveline, like doing a brake stand but not fully releasing the clutch or moving the truck, just to see how much the engine and driveline move. do this in forward and reverse.slide under it when it cools down and look for shiny spots at tight clearance areas. if in doubt mark the tight spots with something removeable, like a grease pencil or kids' wax crayon. then go for a ride and redo the noise. come back and check to see if there are marks in the crayon. leave it in gear, hood up with some eyes on the engine, rock the truck back and forth to see if the engine rubs anything. can you reproduce the noise when not moving, torque the driveline in forward and reverse and listen/look
it sounds like a tire rubbing but obviously you have checked that. driveshaft rubbing would be obvious as well. does it have a 2 piece driveshaft, check the centre bearing? trans and engine mounts not bottoming out? fan not rubbing the shroud? rear axle C clips not allowing lateral movement of axle? again, post some pics with detail of under hood and driveline. maybe we can see something you didn't

Re: Loud Vibration On Turns 56 Chevy Truck
 

the noise seems to be affected by suspension travel as indicated at 19 and 46 second marks of the video
i'd be inclined to say you have wheel rub, since it happens as turning g-force pushes the truck sideways
and it seemed worse when the suspension went down in the turns
look at the rear axle tires to see if you see minor scuffing on the tires, or any black marks on the wheel lip paint, it won't be much

possible causes: too wide a tire, wrong offset or sloppy shackle pins allowing the rearend to move sideways
i had a 59 3800 panel that had similar problem/noise, it also had 12" tires on back with stock suspension
i also had less than 1/4" clearance between the tire and the fender lip
i ran it that way for years without a problem, mostly due to lack of suspension movement with 1 ton suspension :D
3800 trucks came factory without shocks for this reason, no mounts on the frame or axle
the noise reared it ugly head when going thru a squat suspension swale or cornering hard at speed

Re: Loud Vibration On Turns 56 Chevy Truck
 

Ogre hit on pretty well what I was thinking Something rubbing on the tire in the turn that has just enough clearance to not hit when it is going in a straight line.

It could be fan blade hitting the shroud or the front pulley hitting the frame if the clearance is close and the mounts are soft.

Re: Loud Vibration On Turns 56 Chevy Truck
 

pics please.

Re: Loud Vibration On Turns 56 Chevy Truck
 

as a few others have said, sounds like tire rub. just as you are getting off the on ramp, it looks like you go over a seam in the concrete and you can hear the rub sound. Also every time you let off in a corner, the vehicle will load up on the font axle and cause a rubbing type noise.

Re: Loud Vibration On Turns 56 Chevy Truck
 

If it is happening during turns, it could be the bearing races. If they are worn you will get noise during turns when the bearings side loads the races. Are your bearings and races new?