vibration

[squeeezer]

ok so i just fixed the camaro vibration @70mph with the stock d.s.
bought an e-bay speacial aluminum 4th gen shaft=junk vibrated so bad @ 80 cant even drive it and had to replace the new pinion seal (screwed again on e-bay purchase=im done)

balanced the stocker vibration is gone car fixed

so on to the trans am
replaced flimsy torque arm with an umi adjustable unit that attaches to a trans crossmember to lower my 60'
now i have a vibration usually at 3500 rpm or so in all gears depending if the converter is coupling
so i thought uh oh here comes trouble
then i remembered i replaced my trans mount last year after tearing my stock rubber unit (energy susp. polly mount)

so i swapped my trans mounts in both cars
the camaro=stock rubber
t/a =polly

vibration gone.....now ill just rip another rubber trans mount...lol
at least i know what the problem is i can deal with the vibration if i replace it with another polly

and i did not get a vibration in the camaro with the polly cause it has the stock mounted torque arm


just thought id share in case anyone else comes across this or a similar problem

ive been hunting vibrations down lately at home and at work
this one problem came almost 2nd nature im glad cause i know sometimed people spend lots of money chasing these things down and im not immune

[Knarley Darley]

I built a 94 bird with a LT-4 based 383 and a vortex T- trim super charger back in the day, and it had a global west torque arm with a Strange engineering bolt in 12 bolt rear end. We like you chased vibrations, and one of the things we did was use the stock trans mount and I just made a limiter so it wouldnt tear it apart.

[240Z8]

All my projects since 1986 to current have been non stock engine and trans swaps. One of the biggest frustrations was driveline shakes. The thing I always check now for perfection is phasing of the driveline, vehicle loaded with appropriate weight, sitting at running height and really firm mounts. A good angle gauge, lots of measurements can take a lot of the guess work away.. A worn, soft, or slightly different mount at the transmission or rear end can throw the whole works off. So can having the rear pitch up under hard torque.
On my Z I have all poly mounts, bumper to bumper. When Installed the new rear system with redundant top and bottom mounts, I had to drop my transmission about .25". I have super short driveline, shorter than my forearm, so angles are probably more critical.
That 1/4" made the difference of shaking the mirrors and hitting 150+ smooth as silk.

[Supershafts]

[af2]

[Supershafts]

[10sec.et]

[af2]

[Supershafts]

[squeeezer]

so how do you 2 know that you are at a true 0 deg. under load?????

[Supershafts]

You have to find out what your pin moves, every susp is different.

Some link type can move as little as .75 or as much as 2, leaf can move as little as 3 to as much as 4 or 5....

Once you know what your pin changes under load you can adjust for it to be at 0.

[squeeezer]

[quote="Supershafts"]You have to find out what your pin moves,








huh????

[af2]

Pinion"

You can get a good idea using a bottle jack and angle finder.

[10sec.et]

one of you guys explain this in laymans terms for those of us that are a little slow . exactly how would one determine the precise pinion angle while under load ? not being a smarta$$, i simply dont know.

[squeeezer]

yeah......iset mine @-2deg
for a torque arm suspension cause it was what was recomended
so how do i know if im runnin 0 under load

i dont have a vibration problem im just asking