Alex41

iTrader: (14)

Ok...I'll try to explain this as easily as I can without forgeting everything I've done to try and fix it.

I have a vibration at 65-70 and up that shakes my hand on the shifter and my passenger seat unmercifully. It seems that it gets worse the more I drive it on longer trips but It still does it in the garage with jack stands on the rear end.

What's been done:
Tires balanced twice
Swapped from auto to manual (I just wanted a 6 speed)
Has tubular non-adjustable control arms
Tubular non-adjustable panhard bar
Edelbrock fully adjustable torque arm set at -1.5 with the help of MWC
TA rear cover
New rear rotors
SFC's
New axle bearings
Checked for bent axles
New aluminum stock drive shaft
Checked pinion for slack
Checked carrier for loose bolts and deflection
Lowered on Eibach Sportlines but vibraion was there before and after
New Bilstein shocks
Energy Suspension trans mount (stock rubber one had same result)

I've tried everything I can think of to rectify this issue. It literally puts me to sleep after 2 hours of driving and I have a 9 hour trip coming up in a few days.

Does anyone have any experiences they want to add here that may help me out? I'm really bummed here since I've been through 3 f-bodies to get this one. I want to keep it but it's making me very unhappy at the moment.

SVThuh

iTrader: (2)

Is it ONLY speed related or is it also RPM related? If so, check your flywheel for balance.

Have your driveshaft balanced (I know, its a stocker and it should be fine) but have it re-balanced. Replace your U-Joints also.

Have you checked your rotors? Does it feel like they are 'warped' at all?

Did it vibrate while it was an Auto? If not, check everything that was changed. Its not likely that a vibration will just come out of nowhere..

Good luck!

Alex41

iTrader: (14)

Just replaced the rotors today with no change.

Vibrated with auto and 6 speed with no change.

Went from stock steel to stock aluminum driveshaft with no change.

Both shaft's U joints are tip top.

Yes, it's only speed related. RPM's have no effect on the vibration neither does drag on it since it still shakes in the air.

SVThuh

iTrader: (2)

You have me stumped.. I can't think of any other possible reason right now.

6spdchevy

iTrader: (2)

motor mounts?
what type of exhaust do you have?

Vexzer

iTrader: (1)

Have a passenger in a following car observe yours during the vibration period. Have the observer carefully watch each wheel, start without assumptions about what you think you'll see. Also have someone drive the car while you watch it from another vehicle. Jack up and check each wheel -AND each tire, for out of round or true. Pull the rears & insure the wheel studs are straight [no, I am not kidding -I bent mine at SAR after some wheel hop]. Better tire/alignment shops [Bear Wheel & Alignment in San Antonio] have road force testers that can measure if a tire has a hard or soft spot that makes it feel like a bounce, but otherwise looks and balances OK. Avoid Discount Tire -They will charge for road force and tell you 3 of the 4 are bad and the 4th should also be changed. Good Luck!

Turnin20s

iTrader: (12)

Possibly bent axle? Or broken belt in a tire? Otherwise its hard to say. I had a horrible vibration when I swapped to the 6 speed and found it to be the driveshaft. Swapped to an aluminum shaft and the vib went away.

Also do you have an adjustable TA?? If so double check the pinion angle

Houdini

iTrader: (2)

Had this happen to me once... ended up being a bent passenger side stock axle.

Couldn't figure it out until I had a friend drive my car and I followed in his. Passenger side rear tire had a slight wobble to it at speed... stuck out like a sore thumb if you were looking for it.

tpunk

iTrader: (8)

This happened to me once. Ended up being the tire was starting to come appart (couldn't tell from the outside). You could also check your wheel bearings/hubs.

Alex41

iTrader: (14)

I really don't know how the hell the guy at Discount Tire missed the 2 bent rear rims?!?!?!?!!!!!!!

How the **** does a place stay in business with total jackasses working there. I took it to Firestone today to just bite the bullett and buy 2 new rear tires since I really don't care for Premwell(sp) tires anyway. Once the new firehawks were on then he put it on the ballancer to road force balance the tires and sure as ****....they were out of round and wobbeling around.

I have spent nearly a thousand bucks chasing a problem that could have been taken care of if some stupid ******* had done his job properly the first time a few months ago. ****!!!

SVThuh

iTrader: (2)

So I take it the problem is fixed now??

Awesome! Glad you got it fixed! Enjoy your road trip now!

Turnin20s

iTrader: (12)

The rims were bent so you replaced the tires and now its fine???

Sounds like you bought some cheap tires and the belts were seperating. I had the same problem with my DD, the previous owner put some cheap Farm & Fleet special (AMERAG4S) tires on it and after a long trip on the interstate at 75 mph it started to shake. Turns out the belts seperated, new tires and its good to go again

Glad you got it fixed, too bad you had to replace so much to find the problem

Alex41

iTrader: (14)

No, its not fixed. I resolved that I needed new tires so I figured it would be best to just get them and hope that it fixed the issue. While I was there the guy called me out and showed me the rim moving all around. We decided to just road force balance them and hope for the best. Needless to say it didn't work. I'm still trying to find a company in the city that can straighten them out in time. Any suggestions locals?

formula vincent

iTrader: (1)

wheels america in dallas . they did a hell of a job on my wheel .

Vexzer

iTrader: (1)

Stay off the curbs! haha

Alex41

iTrader: (14)

Well......I had the wheels fixed but they weren't the bulk of the problem. Yes, the car is a bit better but it still has the shimmy in the seats at 65+. I'm out of time to get it fixed before the road trip so I'll just have to see how badly it shakes on the way but damnit, I don't want to deal with this anymore.

Alex41

iTrader: (14)

I just tried swapping the front and rear rims with no change so it's not a wheel issue this time.

All I can figure is that one or both of the axles are just so slightly bent that I couldn't see it when I took them out and rolled them on the floor.

Do all stock 10 bolts have 28 spline axles, because mine has them? I also have arp studs holding the center section to the housing so I'm inclined to believe someone has been in there before.

Vexzer

iTrader: (1)

Potluck attempt at best. If one or more is bent, well, it was still on the car when you re-tested...

Not how you check for a bent axle. The bend is in the relationship of the hub to the shaft. With the axle reinstalled, rotate it against a dial micrometer for runout. Harbor Freight is your friend.
http://www.harborfreight.com/clampin...tor-93051.html

Alex41

iTrader: (14)

Been a while since I've updated this thread. I like to finish what I started so in the future, when people are researching this they can see what fixes the problem.

Since I last visited I have replaced the axles with known good ones, replaced the yolk on the pinion, and replaced the tubular control arms with stock boxed ones.

NONE of this has helped. I finally got a friend to ride along and he is as baffeled as I am on this one. The time has come to bite the bullett and take out the last piece of the puzzle.....the rear end. To hell with this 10 bolt crap!!! I have a Moser 9" housing with MWC center section 3:70 geared posi unit on the way. I'll post as soon as I have it installed and broken in.

mitchntx

iTrader: (14)

Have you recently had a clutch failure? Did you change the pilot bushing/bearing?