WS6FirebirdTA00

iTrader: (33)

I noticed this today getting on the interstate. When I load up the car and get to about 90 or so and then back out (clutch in) I get an odd vibration which feels like it is from the rear of the car. It seems to go away when it is back in gear and I load it back up. Sort of difficult to tell for sure, but that is how it seems.

Only thing I can think of would be to check the torque arm bolts and pinion angle out. I dont know if that speed when it unloads if there is too much negative pinion angle and is causing a vibration. Any ideas that would help are appreciated.

mitchntx

iTrader: (14)

U-Joint?

If it's an M6, does the shifter dance around? Maybe a trans mount?

98_1LE

iTrader: (17)

Have the balance checked.

WS6FirebirdTA00

iTrader: (33)

Tranny mount is brand new, as is the u-joint.

RE AND CHERYL

iTrader: (31)

I've got the same thing. Never tried it with the clutch in but I notice it when I let off the gas above 70mph.

WS6FirebirdTA00

iTrader: (33)

Checked my pinion angle today and it was off a little bit, so we will see...

gollum

iTrader: (1)

This may help

http://buickperformance.com/Pinion.htm

02Z28LS1

iTrader: (2)

are your LCA's still stock? if so, the bushings may be worn out.

i think that's what is causing weird vibrations on my car in the same types of situations as you, when unloading the rear, and sometimes braking.

when i was under the car installing my sway bars, i grabbed my LCA's and tried twisting them, and they were both able to be twisted by hand, especially the passenger's side

i've got new LCA's on the way, so hopefully it will get rid of that, cause it's getting REALLY annoying.....

WS6FirebirdTA00

iTrader: (33)

Stock LCAs went to the land fill a few years ago.

jb442

iTrader: (4)

Did changing the pinion angle help? I had the exact same problem with my '69 442 after I made some changes to the rear suspension for drag racing (relocated the upper control arms), which changed the pinion angle. After I stopped racing the car, and put the suspension back, the vibration went away.

WS6FirebirdTA00

iTrader: (33)

I have not been to those speeds to check it (and dont want to do it to just check haha). Hopefully it cures it, it is the only thing that would make sense.

oange ss

iTrader: (50)

too much neg pinion angle will cause the vibraton you described..also too much pos angle will cause vibration when loaded but go away on decel...fwiw

WS6FirebirdTA00

iTrader: (33)

thanks

bad6as

iTrader: (17)

drive shaft critical speed? i have the same problems mods in sig, i think its my d/s