Hello

My car is 1980 Olds Delta 88 ex-diesel, now 307 with (original?) TH350 tranny, non lockup.

I have strange vibration at 60mph. It starts as a small shake at 55mph (you can see backrest vibrating). After that at becomes more annoying. Chassis starts regular vibration so vibration must come from spinning part. This vibration doesn't stop me from driving my car but it's annoying in the long run.

I have changed rear shocks, U-joints, driveshaft (it was rubber type and twisted), small block springs in front, and my tires are new and balanced.

Could it be bad transmission tailshaft bushing and yoke? My car is an old taxi and has high mileage on it.

Another type of shake is in steering wheel. This shake is irregular and comes only in some kind of asphalt roads. Could it be bad front shocks? They looked pretty old.

 

Had the same issue with my 66 Olds, and went through many of the things you have done. Through the process of restoration I had a new driveline built, rebuilt the trans and rear axle, changed the tires, on and on but still with that annoying vibration.

Finally resolved after changing the rims on the car. The wheels always balanced correctly, didn't wear tires abnormally, didn't show any sign of being bent on the balance machine, holes for the studs weren't out of round or worn, but they created that 55 mph + vibration every time.

Might be worthwhile to look into, good luck.

 

if it is not in tire and wheel balance, check the transmission mount.They sometimes go bad and let the driveshaft get out of line enough that the U-joints will be out of line and cause a drive line vibration. Good luck ,Larry

 

I have been hearing that the tires these days are JUNK.... As with everything in the manufacturing these days ...NOTHING is up to good specs.

I have vibrations in MANY of the vehicles I have... all around 55-70 and usually it is tire or wheel balance issues ALWAYS...

the steering wheel shake could be steering components tie rod end ball joints even the steering box on an old taxi you have alot of turning miles.

We get a lot of vibration calls when rear ends are done with steeper gearing the steeper gears make the whole drive line run at higher RPMS and this causes body booming and vibration of parts that are just not up to taking the new more violent RPM speed of the engine trans and drive shaft are now spinning at.