spinedoc

Ny 80 has an unknown vibration in car. It only occurs in gear and on the gas. In nuetral or while coasting it isn't as noticeable. The shifter shakes, the noise is loud, it's horrible.

Heres what I have checked: Motor mounts, 4speed, halfshafts, driveshaft, U joints, Crossmembers, wheel bearings, shifter, linkage, clutch, rearend attachment bolts, camber struts, crank pulley.

Any advice would be appreciated. I hope it isn't in the motor somewhere.

stingraymaniac

is the engine sounding ok?
maybe the shaft is off balance?
sounds like a ujoint to me but you have checked them all?


:smash: :smash:

Fevre

Also check the rear snubber bushings/cushions, the ones at the of the diff bracket. The nut came off and allowed the bracket to rotate up and down making a vibration, might have been making noise too but could not hear it over the Flowmaster 40's with the top down.

Brown78

Sounds like #1 a bad U-joint or #2 out of balance drive shaft. I would start with the u-joints. Keep us posted on your find. :seeya Steve

john V. zemba

harmonic balancer rubber seperating

toyvet1

tailshaft bushing..

spinedoc

The motor sounds OK, I haven't noticed anything there, I thought maybe a slug of mallory metal came out since motor is internally balanced, havent wanted to pull motor yet. I had the 4 speed rebuilt, so I assumed they would notice a bad tailshaft bushing(?). I had the shafts trued and balanced, and the local speed shop looked at the shafts and u joints and said they seemd good, no wobble or slop. Can u joints be bad without outward signs? I guess i could change them all, but don't wan to waste money. How can tell about the balancer rings seperating. I have looked at that, and it looks good, but I am not sure what to look for? The car is at the spped shop today, hopefully they will find something. :confused:

stingry

Another guy oseas has a similar vibration and had it over a pit to check for noise from underneath. Is the vibration speed related. Does it do it under load, constant speed or braking.

Some of these are simple and obvious but humour me.

I would get the car on the lift, get three friends and each go around and try and wobble/move everything bolted to the car. Check the side yokes of the diff. If these are worn then you will get outwards thrust under power and will notice vibration (bad). Was the driveshaft balanced? Is it still straight? Put a engineers straight edge on it and see.

When was the park brake last checked? There are springs holding the shoes inside the hub. Are all your wheel nuts tight? Are all the wheels balanced. I have a tire on one wheel that just won't balance, rim is fine but tire is out of shape.

Good luck.

spinedoc

I put the car on a lift, tightened every bolt, even removed some and loctited them back on. The rearend has about 3000 miles on it. It is from Tex racing. I broke in according to instructions and haven't had trouble yet. It came as a whole unit, with the batwings etc. I have had all shafts trued and balanced. I have no parking brake or any related hardware. I have had all tires reblanced and torqued all lugnuts to spec. I even put different wheels and tires on it, still no good. How do i measure wear in side yokes? Do i need to pull halfshafts again? Thank you for any advice. Eric
]

The vibration only seems to occur in gear and under load, any gear, any speed will do it.


[Modified by spinedoc, 6:55 PM 4/2/2004]

12stepvette

I know you guys are are gonna be skeptical when you here my vibration issue...It was very noticeable under load...a highspeed vibration that I thought might be a drive shaft or half shaft out of balance...around the same time I was replacing valve stem seals and adjusted my valve train per Lars tech paper....I have to tell you....this baby is now smooth as silk and purrs like a kitten...just my 2 cents :chevy

isosceles

:lurk: