92 5.0stang

My car started shaking really bad all of asudden at 80mph- 100 mph and after 100 it starts to even out but that could just be because i cant tel anymore. But i thought it was the alignment or tires needed to be balanced. but thats not the problem had all of that done and still does it. Its a 5 speed and the stick was shaking so badly that it broke the roush shifter ball i had on it right off of the thing it was glued on to. and now i cant use that so any ideas??????

19stang88

u joint, drive shaft needs to balanced. harmonic balancer maybe.

92 5.0stang

im pretty sure i had the u joint and harmonic balancer replaced about a thousand miles ago not exactly sure no more than that. could something go wrong if they were that new. the drive shaft sounds like the problem. if it is the drive shaft or any of those is it safe to drive ???

Frostbitten

could be a worn out bushing somewhere in the front or rear suspension

karvounas

check your rear suspension.

Vader GT

Sounds like the driveshaft. My 1990 did the same until I replaced it, got the FRPP aluminum unit, What a difference!!

92 5.0stang

Is it safe to drive on the turnpike

19stang88

well if you are always driving at high speeds you should not drive, because if something is vibrating that bad, it usually means something is bad. Try a new drive shaft, an aluminum one from FRPP

mstngsule68

go see if ur tires are out of balance

Jfsram

He said he had that done but it's a good time to point out that a tire may be out of round and it can still be easily balanced.
Something even many tire technicians fail to realize. For example a flat spot in the tread will shake a car but may still balance zero, zero.

Personally though, I don't think that would knock a shifter emblem off. That's most likely driveshaft or u joints. Check the runout of the driveshaft. It should be less than 0.020".

If you suspect the harmonic. Just drive it to the speed of the vibration and shift into neutral.