car shakes at 90mph any ideas ?

[fasta**z28]

Hey every one just took car out for a drive on highway did 140mph was fine on my way back home i was in 5th and at 90mph and started to accel and alll of a sudden shakes like it was coming from tranny or shifter? does any one think this is the tranny, drivshaft or wheels out of balence?opinions please

[fasta**z28]

this happens only as i let off the gas at anything over 90 mph anything under is fine ?

[TrickrTreat]

i would say drive shaft.

[fasta**z28]

thats what i was thinking is it out of balance , u joint , just wanna no the prob before i start my build so what's a great shaft bang for $ for my build application this winter can i swap for ls1 ,le1 alum or am i gonna need stronger?

[Batman]

for a 383 I'd go steel from Spohn or Denny's

[fasta**z28]

so def no alum how bout the Denny's "nitrous ready" driveshaft is that what your refering too?

[ILuvPizzaTimes10]

what torque arm are you using? adjustable? its your pinion angle Not your shaft. if shaft was out of balance youd feel it at a much lower rpm/mph whether on or off the gas. double check pinion angle.

[DemonWithin99]

tail shaft bearing on trans? or drive shaft would be my guess. I have a simmilar issue, have for a while plan to re balance d/s, and new u-joints.

[black heartbeat]

I say slow down if you are going 140 on the highway lol

[fasta**z28]

Originally Posted by ILuvPizzaTimes10

what torque arm are you using? adjustable? its your pinion angle Not your shaft. if shaft was out of balance youd feel it at a much lower rpm/mph whether on or off the gas. double check pinion angle.

bmr adjustable Here's what I did
Jacked the rear of the car up and i popped the hood
then i Placed angle finder on front face of pass side head i then Jacked up car until it read 0* Now the engine and the trans are centerline exactly level. i then Placed angle finder on bottom of pinion yoke and set the Set angle. it all seems to be correct so thats scratched off i then took my driveshaft out and damn the u joints are shot, my buddy had took it to his shop checked to see if my driveshaft was unbalenced and he said it looked fine until it hit high rates of speed he then told me to turn it 180 degrees and try that that didnt work so i am asuming thats the cause of the vibrations so to the trash that goes and off to a new one thanks for the opinions!! help very much