Viabration from center to back at 45mph and up - Page 2 - Resolved Drivetrain Issues - Firebird Nation

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Viabration from center to back at 45mph and up


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#21 electrobrandino

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Posted 27 April 2009 - 05:31 AM

a little ranting every once in a while is needed man :peelout:

Give em hell :shots22:

#22 Scotts 98

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Posted 29 April 2009 - 07:30 PM

Bob, This might be some good info and I wish I was pointed to it when I was trying to figure out my vibration problem. Found out I just cant pull out my two piece drive-shaft and install a one piece. Gm set the trans angle and pinion angle for the two piece. Any how, I did post the angles I measured and sure wish someone would have caught it. I'm running the driveshaft at such an angle that it is not canceling out. There should be an angle that is opposite on each end and enough to spin the bearings. So I have to raise/shim my trans up so I get a pos angle that is equal to a neg angle that is measured at the pinion so that there is cancellation. In the stock configuration after putting in a one piece DS...

Rearend angle to driveshaft -.8
Trans angle to driveshaft -1.5

I need to set it up for this:
Rearend angle to driveshaft -2.0
Trans angle to driveshaft +2.0
This should cancel out all my viabrations.
Good info read from here...
http://www.prostreet...om/dshaft.shtml
Will post my results...
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1968 Dodge SuperBee
383 Magnum
Auto

#23 FBN Firebird Nation

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Posted 29 April 2009 - 07:48 PM

Good info scott, this will certainly help others who have the same problem.

#24 Scotts 98

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Posted 01 May 2009 - 07:46 PM

Well I could not get the tranny up enough to get a correct angle without cutting the floor! So after thinking about it I decided to put my adjustable tunnel brace mounted torque arm back in and return the tranny to stock position and set it like this...
Second pic is about how it was with the stock torque arm and a one piece DS.
My engine tranny sat at 2.5 deg pointing down so I had to adjust the pinion to 2.5 pointing up and the DS sits at 0.

Hope it works, I'll have to take it for a spin in the morning.

Edited by scott-leanne, 01 May 2009 - 07:48 PM.

1968 Dodge SuperBee
383 Magnum
Auto

#25 Scotts 98

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Posted 02 May 2009 - 08:47 AM

It worked so far. Did not notice the out of round tire sound and feel from before. The ride is a little noisy because the point where the tunnel brace and arm meet has urethane bushings so it lets more rearend and road noise in to the body. So far I only took it up to 70mph and it seemed ok.
I hated to set the rear pinion up at such an angle as it goes against everything I've read but I think the tourque arm is so stiff that it wont let the rear end rotate much during hard launch's plus there is only 200 hp.
After the test drive I checked the angles just to make sure and found the engine sits about 2.5 to 2.75 deg pointing down, (hard to see exactly ) and the rear is at 2.5 deg up. Posted Image
1968 Dodge SuperBee
383 Magnum
Auto

#26 95LT1Bird

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Posted 02 May 2009 - 10:50 AM

excellent link to the driveshaft angle website. it gave me hope once again to try my ongoing vibration.
1995 Firebird Formula. LT-1 6 speed, underdrive system, k&n cold air intake. Flowmaster exhaust no cats. Pro 5.0 6 speed shifter, Riken Raptor tires, Richmond 3.73 gears, tune by PCMforless.com, 2001 WS6 Aluminum Driveshaft , Clarion DXZ865MP mp3 player. 6x9 MB Quart rear speakers. MB Quart front speakers. Alpine 100x2 amp on 6x9's. Infinity 10" DVC sub, stealth rear sub box, Memphis 500x1 amp, 5% tinted windows.
Coming soon: Subframe connectors, SPEC stage 2 clutch

#27 Scotts 98

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Posted 02 May 2009 - 07:19 PM

It worked so far. Did not notice the out of round tire sound and feel from before. The ride is a little noisy because the point where the tunnel brace and arm meet has urethane bushings so it lets more rearend and road noise in to the body. So far I only took it up to 70mph and it seemed ok.
I hated to set the rear pinion up at such an angle as it goes against everything I've read but I think the torque arm is so stiff that it wont let the rear end rotate much during hard launch's plus there is only 200 hp.
After the test drive I checked the angles just to make sure and found the engine sits about 2.5 to 2.75 deg pointing down, (hard to see exactly ) and the rear is at 2.5 deg up. Posted Image


I should have said that I checked the eng/trans angle at the harmonic balancer. It's supposed to be a good spot since it's a straight shot to the output of the trans.
I'm thinking I might be able to shim the trans up a little and see if I can get it closer to 2.o deg. If it works, at least there will be a little more wiggle room for flexing.
1968 Dodge SuperBee
383 Magnum
Auto

#28 Scotts 98

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Posted 03 May 2009 - 10:17 AM

OK, took it up to 80 and there was some vibration and a wa____wa____wa____ harmonic.
Did not like that too much. http://www.firebirdn...tyle_emoticons/default/headscratch22.gif
Decided to shim the tranny mount up a total of a half inch. Pulled out the DS to measure the angle of the tranny and it sits about 2 deg down. I also adjusted the torque arm for 2 deg pinion and it is up. All back together, took it out for a spin. No more harmonic noise and no vibration @ 80mph. I think I got it. I'll know tomorrow going to work. The biggest thing I noticed was no wheel or suspension shake and really goes straight. Amazing what an out of balance DS will do to everything. I was chasing my tail on this one. I'm crossing my fingers.


Scott http://www.firebirdn...tyle_emoticons/default/stuart.gif
1968 Dodge SuperBee
383 Magnum
Auto

#29 FBN Firebird Nation

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Posted 03 May 2009 - 11:27 AM

Thanks for the update scott, I hope you got it figured out this time.

#30 Scotts 98

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Posted 09 August 2009 - 05:11 AM

Well well well, All my vibration problems were do to BAD wheel balancing!:16DAMNIT: Walmart :crap: , tires plus :crap: , farm and fleet :crap: , sears :crap: , ALL SUCK ASS. :rippedhand22::plzdie: :16DAMNIT: Took my tires to Beaumont Tire and Auto in Champaign, IL and all my problems went away.
I cant believe that around here, if you go get new tires put on and your car rides like a flinstone mobile, you would think that something else is wrong and the place where you had it done won't budge and tell you it's you car, not their tires or balance. That is what happened to me. I replaced the whole suspension and steering system for nothing. If you have vibration, suspect the wheel balance. I don't even want to add up the cost of all the balances and parts I've put into to this car because its make me so mad, I can't even see straight. http://www.firebirdn...tyle_emoticons/default/growl22.gif
It is not a law that tire shops have to calibrate their machines and I think that sucks. Wish I would have found this out a year ago.Posted Image
Scott in the middle of billy bob hey seed Illinois....:tard: Auto mechanic around here...

Edited by scott-leanne, 09 August 2009 - 05:25 AM.

1968 Dodge SuperBee
383 Magnum
Auto

#31 TransAmer99

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Posted 10 August 2009 - 04:58 AM

Geez, Scott, that really blows! All the time and resources you poured into trying to fix the problem. I'd be half tempted to take Walmart to court over it, along with all the other incompetant shops you've been to. At least file complaints to their head offices and perhaps the BBB. Occasionally, a company will try to make good by offering you some sort of satisfaction.

I started reading your tread, not realizing it was several months old. When I first got LadyHawk, I had a very pronounced rearend noise that changed pitch with speed. After spending $2500 on new tires, brakes (which were definately needed) and front wheel bearings (just as a precaution), It was still there, but more of a sound and less of a 'feel'. Since I was over 80K on the odo, I had the gearset replaced. No more problems after that!
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Posted Image

Rest In Peace, Pete, a.k.a. "Brother Rat" and Jay, our Firebird Brother!
Y'all two keep each other out of trouble up there, okay?

#32 Scotts 98

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Posted 10 August 2009 - 02:24 PM

This has been more of an out of round tire feel and the faster I went the worse it got. Guess I should of went to Indiana for tires...or Oklahoma where the speed limit is 75mph and I can imagine at that speed there would be a lot of complaints if the wheels were out of balance.
1968 Dodge SuperBee
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Auto

#33 mark1963

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Posted 20 May 2010 - 02:56 PM

WOW, i have been having that same intermittent vibration since i bought my 02 bird a month ago, i had every thing from front to back checked out at GM, the only thing was found was a small leak from the rear end cover, getting fixed monday,, to the vibration problem, i brought my car to tire kingdom twice to have balanced and still not right, i will have GM do a true balance monday, after you had yours done up right by someone that knew what they were doing, did it fix the vibration issue,????




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