[78mach1]

alright so on my 88 gt its got a vibration while hard accelerating, its a stock 5.0 with a aod, when ever i get on it, it will start vibrating at about 4000rpms and then stop at about 4500rpms, its definatley in the drive line. basically i would like to know possible causes for this, and i hate to say it but it almost feels like a transmission problem

[93hatch]

driveshaft unbalanced? rear end going out?

[Iownastang]

Originally Posted by 93hatch driveshaft unbalanced? rear end going out?

if it was the driveshaft you would feel it at all rpms most likely

[78mach1]

it only does it during hard acceleration and then it goes away.

[REIGNYC]

Dude Check Your Exhust Make Sure The Brackets And Welds Are All Connected !!

[78mach1]

ya its not that, the exhaust is all new and i have re torqed all the bolts 3 or 4 times. it feels like a drive line issue

im just trying to get this car smoth and buttoned up good cause im thinking of selling it

[baine21225]

my friend had a similar problem, spark-plugs were bad.....it would shake and then go away......changed them and its like a brand new car

[78mach1]

Originally Posted by baine21225 my friend had a similar problem, spark-plugs were bad.....it would shake and then go away......changed them and its like a brand new car

im pretty sure it has nothing to do with the engine because it runs smooth the hole time, and i have done a tune up (plugs, wires, cap, rotor)

[86_Notch]

this may sound stupid but check the driveshaft bolts, i chased a similar vibration for a long time before i realized my bolts were coming loose !

[ujslost]

Originally Posted by 86_Notch this may sound stupid but check the driveshaft bolts, i chased a similar vibration for a long time before i realized my bolts were coming loose !

Actually thats not a stupid idea. I have seen it happen.

Jack the car up in the rear scotch the front tires. Put the car in gear, dont give it throttle let it idle. You or someone else look under the car and watch the drive shaft see if its bent. And inspect it for dings or missing counter weights.

I had this problem.I swapped the driveshaft out for a known good one, and the vibration was gone. So I bought another shaft. problem solved.

[trueblue01]

Sounds like a driveshaft issue. Check bolts ^ then joints. Also if the bushings are worn out in the control arms, the pinion (front of the gear case) can roll upward enough under hard acceleration to change pinion angle and cause a harmonic type vibration. Improperly set adjustable control arms can do the same thing.

[REIGNYC]

Well DUDE !! when you fix it might as well keep it cause now its new !! LOL !! anyway gl if its not exhust it most deff could be the drive shaft but it could also be the TRANSMISSION CROSS MEMBER who installed it check its BOLTS as well

[foggyracing]

a friend had a similar problem and ended up being a u-joint

[91cobra5.0]

Originally Posted by foggyracing a friend had a similar problem and ended up being a u-joint

are u joints hard to replace in these cars?

[trueblue01]

No. Couple hours max including removing the shaft, even less if you have a press or large bench vise. Replace them with Spicer brand, not the cheap Chinese made ones.

[1slo5.0]

Originally Posted by 86_Notch this may sound stupid but check the driveshaft bolts, i chased a similar vibration for a long time before i realized my bolts were coming loose !

+1

I've had that happen numerous times.