motro

Okay,..I know I don't own my 63 anymore but I still need the best advice about a car problem. So where do I turn, of course, to this forum.

My 69 Z28 has a serious vibration after 40 m.p.h. The wheels were just balanced and my guess is the driveshaft. I know it's not the engine because when I accelerate to 50, I get the vibration after I put the tranny in neutral.

Now, the car just had a frame off resto so everything should be okay. I'm stumped. Any ideas?

kcust62

You mentioned a frame off resto, so, assuming the tranny and rear differential were rebuilt along with replacement of the driveshaft u-joints, axle bearings, etc., I would double check the ring and pinion lash in the rear end. There may be excessive play in the gear mesh causing the vibration when torque is taken away from the drive train. i.e. (throwing it into neutral). Just a thought. :thumbs:

67L36Driver

A wheel bent or a tire out of round??

JohnZ

Driveshaft out of balance, worn tailshaft bushing, or incorrect U-joint angles; could also be radial or lateral runout in the wheels/tires. Find a shop with a Hunter GSP9700 machine, and it will identify both runouts and any radial force variation. Go to http://www.gsp9700.com to find the shop closest to you that has one. :thumbs:

motro

Thanks, that makes a lot of sense. Instead of guessing at the problem, do some testing to try to pinpoint exactly what's wrong. Thanks again.

Dyna

Maybe you just threw a wheel weight, or something easy like that.

Dyna

ro.co3

I had a bad shake at around 60. Had it in about four shops trying to find the cause. Thought I'd never enjoy driving this car when finaly somebody spoted a bad pitman arm. Drives great now, so keep pluging its got to be there.