silversrtman

iTrader: (20)

my buddy and I both are having speed vibes at around 55+mph and we for the life of us cant figure it out. Anyone not have any vibes? Anyones sun visors not shake? Can you guys see out of your sideview and rearview mirrors? If so please share your suspension and drivetrain setup. Thanks!

tremiles

Tires with uneven treadwear, out of balance wheel/tires, worn bushings/ball joints/tie rod ends, bent rims, bad alignment, improper tire inflation can all cause vibes at speed. Things that you can check yourself are tirewear, inflation, and tie rods. Get the front up on jackstands with the tires straight forward. Grab one of the front tires at 3 and 9 o'clock. Push with one hand, pull with the other hand. If you get any play, you may have worn tie rods. Remove/replace and get an alignment immediately.

SVThuh

iTrader: (2)

^^^^^Good Info^^^^^

If all that checks out, check driveshaft balance.. I have had multiple f-bodies with out of balance driveshafts. Quite inexpensive fix if it is out though.

qwikz28

iTrader: (12)

I see you have an aftermarket torque arm. Is your pinion angle set correctly? Mine wasn't and was causing a dreadful vibration. I have since had it set correctly, and I am now vibration free.

Actually, that was a lie. That only helped it. New ball joints, tie rods, and an alignment fixed the small vibrations I had at 80+ and now the car is completely solid.

silversrtman

iTrader: (20)

That is defintely good info...I am going to try to rule some of those out now though.

My tires are basically new ~5000 miles
My wheels were just re mounted and roadforced balanced
I have not checked my ball joints and tie rod ends, but i definitely will, however its more of a driveline vibration (i feel it through my seats on my butt lol)
Again my wheels were just balanced and I witnessed it first hand on the balancer they are not bent.
The car hasnt been aligned since ive owned it and who knows if the previous owner aligned it...gotta check that out.
And my tire pressures are all good
I am definitely going to check for tie rod play though thanks for your post! If you have anymore input I am all ears!

The thing is, I had the vibration with my stock ds, i borrowed my buddies ds, and now I have a brand new strange moly ds...so I dont think its the ds balance?

I have been toying around with my pinion angle for a long time now, and I have gotten it pretty close, but never 100% gone. I understand that it is an f-body and not a cadillac, but I just want to be able to go fast and not feel like the thing is going to vibrate itself apart. And as luck would have it driveline vibrations are like the one thing i cant stand. Bring on loud exhausts, rattles, anything but the driveline vibes...

And again its definitely a driveline vibration, would changing my ball joints and tie rods help that? Its more behind me...if that makes any sense.

Thanks for the input fellas, keep it coming!

1BAD02WS6

iTrader: (-1)

Alignments don't cause vibes, but if you never had one I would rec one. They should check your front end for you before they perform the alignment

02Z28LS1

iTrader: (2)

don't know if you replaced the u-joints when the driveshaft was replaced, but i'd check those, too

leadfoot4

iTrader: (1)

I'll second the pinion angle and/or the u-joints.

ULTIMATEORANGESS

iTrader: (4)

are your shocks ok?

silversrtman

iTrader: (20)

We both have brand new driveshafts with new u joints

I just re-checked my pinion angle, I used the maddog method (put the angle finder on the torque arm and bring it to -2 and call it a day)

My shocks are stock decarbons with about 45k on them, but my buddy has bilsteins with around 10 k on them

FirebirdStud

iTrader: (5)

I know I am going to get flamed here, but to check your pinion angle you need to set the pinion relative to the engine crank. Do a search and you will find that method. Yes, people swear you can set the pinion relative to the driveshaft and it doesn't vibrate, but that is a crock of sh*t.

I spent 2 years chasing a damn driveline vibration with my dana 60, and the way that mounts in the car didn't line up like the 10 bolt did. I called a speed shop that was local to me in MN and they asked me all the mods, and they said bingo it is your pinion angle. I told them how I set it and that I read it on the interweb and they laughed at me. I guess they hear that all the time, and it is the wrong way to do it. I set my pinion -1 degree from the engine crank, and BOOM driveline vibration GONE! two years it took me to figure this out. UGH. but I finally fixed it. Trust me, set it this way and if it was your pinion angle, that vibration will be gone.

qwikz28

iTrader: (12)

This would be my first move. I was shocked at how solid it made my car. New ball joints, tie rods, and an alignment did wonders to make my car smoother. I don't know how, but it did.

I'm not crazy either.

libertyforall1776

iTrader: (2)

Poly motor mounts will be transferring more vibrations...

BowTieDrifter

i've been having a strange sound from my driveline also. i suspect the driveshaft, and as you said, might as well replace u-joints while at it.
its almost a thumping sound at various points of the rpm range at WOT.

otherwise no vibrations at all!
however my sunvisor does swing back when i romp the throttle though! and swings forward again on the brakes hahaha need velcro or something...

TurbopigB4C

iTrader: (5)

I did not see anywhere but I assume your torque arm is not still attached to the transmission. If it is still attached that seems to cause a lot of vibration.

silversrtman

iTrader: (20)

You are saying having the TA still attached to the tailshaft is causing vibrations? I have a UMI xmember for the TA that i have been putting off installing because I figured it would just transmit all the vibrations right under my *** instead of disappating them throughout the tranny.....Maybe I will install it and see....at this point I will try anything. Thanks for the input

LilJayV10

iTrader: (39)

In for some tech. My junk shakes at 40mph like a ****. I can see the steering wheel shake.

TurbopigB4C

iTrader: (5)

Once I installed my relocation cross member and a new energy trans mount my vibrations went away.

01ssreda4

iTrader: (96)

Bad alignments cause uneven tire wear and THAT causes vibrations. So yes, alignments do cause vibrations. They cost you a pair of tires too.

4valvemach

^^Out of round,cupped,seperated or out of balance front tires

silversrtman you could run the car at speeds with it on jack stands (have the rear up by the axle) and look for anything bent or out of round.