'87 G-body (Olds 442) BAD vibration, help!!!

[kSStamp0182]

sorry for the post, i wasnt sure where to put it, cuz it is my Dad's car so i dont want to fool with joining a gbody forum & i'm sure you guys will be more help regardless, but anyway,

the car is an '87 Oldsmobile 442, with a '87 350 and 700R4 from a totaled R10 (both rebuilt & converted to carb, less thank 5k)

it has a BAD vibration that i have NO idea where is coming from, ive tried everything that i can think of. starts around 55mph, give or take a few, the speedo quit working not long ago (go figure). its bad enough you can see it in the hood and almost feels like the car wants to bounce off the road.

this is what we have done trying to chase this down.
-the rear (10 bolt 8.5") has been rebuilt because it had a whine, eaton LSD, all new bearings and richmond 3.73s.
-new rear bushings and UMI adj control arms
-rear bilstein's
-all new U-joints
-driveshaft was professionally shortened & rebalanced for drivetrain swap
-all engine/trans mounts are good & tight
-pinion angle is set with the rear and trans parallel
-all wheels are balanced dead on to 0.00
-new BFG radial t/a's



i do not know where else to look, the steering wheel feels perfectly fine even during the vib. although none of the front suspension has been touched yet (inspected tho, no visible signs of any damage)

the only thing we havent done to the drivetrain yet is install the torque convertor lockup, but i wouldnt think this would be the cause??

help me out guys!!


ohh & just cuz i know how y'all love pictures, heres the truck the cars motor came out of. RIP ol girl..

[andrewmp6]

I'm a member on a few g body forums only the monte carlo ss one is worth joining.Try driving the car get it to vibrate like it has been the sec it starts pull the car out of gear in neutral if the vibration stops then its in the driveline if it keeps going then its suspension or something stupid.Only dumb thing i can think of is a brake rotor warped can shake like a out of balance tire i found that out the hard way before lol.

[mr48chev]

It is possible that it has a rotor or drum that is out of balance. Find a shop with an on the car spin balancer and have them spin the wheels on the car.
If you can find a shop that uses a strobe balancer so much the better as those are dead on accurate in eliminating wheel/tire /hub vibrations.

If the hood shakes it is usually a front wheel doing it but not always.

The rears can be checked by jacking the car up with a good (big) floor jack under the third member and running the car in gear up to the speed it shakes. You might also want to check the runout in the driveshaft while you have it jacked up.

If the car has full hubcaps on it pop the hubcaps off and take it for a drive without them. I ran into one car (70 something Ford LTD) that had an out of balance hubcap. That was a brand new car brought to the tire store I worked in at the time with a vibration claiming it was the tire.

I spent about six years chasing vibrations in cars on a daily basis and they can be a bit of a booger at times but keep after it and you will find it.

[kSStamp0182]

thanks for the replys guys, i have put it in neutral and it seems to make no change, nor has reving the engine to cruise RPM while in neutral, thats why ive been chasing suspension mostly (it needed it regardless). i'm really thinking its something to do with the brakes as well, or maybe a bad wheel bearing?
no hubcaps, but the on car vibration vib tests are a good idea. i wish i knew if it did it or not before the drivetrain swap, i never drove it then, and dad doesnt remember because he never really drove it.



i told him not to park too close to my '82, dont want it to catch the vibration flu

[andrewmp6]

Pull both sets of brake pads if one side is wore a lot more then other you got a wheel bearing on that side of the car.Or even try unbolting the driveshaft turn it 180 degrees and put it back in.

[kSStamp0182]

Originally Posted by andrewmp6

Pull both sets of brake pads if one side is wore a lot more then other you got a wheel bearing on that side of the car.Or even try unbolting the driveshaft turn it 180 degrees and put it back in.

alrighty i will look, yeah the driveshaft has been on and off 80 times upside down backwards & sideways an still no difference