issue with vibration at 60 mph

[earlbrown]

Why do I feel another ''shop charged me $XXX and fucked my car up even worse'' posts on the way?

[TexasT]

Pretty much. You should have pulled the shaft and taken it to a driveshaft specialist. I hope you turned the boost down or disconnected the wastegate rod. Be sure to check the fender wells and quarter panels for rubber when you pick it up.

[rhturbo]

Car is back with same issue. Will have take it back again tomorrow. Drive shaft was removed and checked, u joints were checked, shocks checked, wheels re balanced (again) Given this is my first GN and I have nothing to compare it to how tight are these cars ? Can I expect no steering wheel shake at 50- 60mph ?  Below those speeds its fine. 

[Scoobum]

I can fall asleep at the wheel with my GN on the 401 it runs out so smooth.

[earlbrown]

Car is back with same issue. Will have take it back again tomorrow. Drive shaft was removed and checked, u joints were checked, shocks checked, wheels re balanced (again) Given this is my first GN and I have nothing to compare it to how tight are these cars ? Can I expect no steering wheel shake at 50- 60mph ?  Below those speeds its fine.

It's a grandma car, you shouldn't feel anything.   Lets get back to basics.

First, jack one wheel off the ground where it's BARELY not touching. Then spin the tire. You're looking for a bent rim or a tire that isn't round.    If those are out, I don't care how much you spend or how many 'experts' lay hands on them.

[Steve Wood]

If it was my car, I would do some of all the above.

I would jack the wheels off the ground and grab each one and see if I could wobble it by grabbing on each side and attempting to wobble it.  In this case, I would be trying to eliminate a bad wheel bearing.  Spinning it should show no run out.    You can check for run out with a dial indicator if you have one.  If it's not visible, when you spin it, it should be good.

Then, with the rear wheels off the ground and the front wheels chocked, just in case, I would start the car, put it in Drive and ease down on the gas gradually until the speedometer is above the normal point of vibration.  If you have vibration, then you know it is in the drive line somewhere.  Get someone to look at the driveshaft while it is vibrating or shaking and see if you have any wobble in the driveshaft.  I would like to think they checked it for wobble in this manner and followed up with a balance check as well as a straightness check.  Many shafts will have a balance weight added to them.

If you found no problem with the rear tires, go back to the fronts.  Assuming you checked the wheel bearings for correct adjustment and they spin properly with little or no run out, I would then check the control arm bushings to make sure one has not disintegrated.  The passenger side rear upper control arm bushing is notorious for being destroyed by heat from the down pipe.  Usually, it is evident by simply looking at it but you can pry on it and make sure the arm cannot move around on it.

If I had not found it yet, A good roadforce balancer will show if the tires are in the normal range of balance and the wheels are true.

You can also check the shocks are tight and the mounting bushings are good.  A google will show you how to check for bad ball joints, tie rods, etc.

Being methodical always helps

[rhturbo]

Car is back with same issue. Will have take it back again tomorrow. Drive shaft was removed and checked, u joints were checked, shocks checked, wheels re balanced (again) Given this is my first GN and I have nothing to compare it to how tight are these cars ? Can I expect no steering wheel shake at 50- 60mph ?  Below those speeds its fine.

It's a grandma car, you shouldn't feel anything.   Lets get back to basics.

First, jack one wheel off the ground where it's BARELY not touching. Then spin the tire. You're looking for a bent rim or a tire that isn't round.    If those are out, I don't care how much you spend or how many 'experts' lay hands on them.

Good to know. At least now I know that this isn't normal.

[rhturbo]

Thanks everyone for all the great advice.This is so frustrating. The steering wheel and front end vibration is bad enough that you would think the problem causing it would be very obvious but apparently not. Certainly a methodical approach to diagnosing this makes the most sense. Its just going to take some time.

[Top Speed]

Could be your a tie rod or the bushing on the upper control arm near the down pipe that fails due to heat.

[rhturbo]

I took it back this morning and they are stumped and have given up so I guess I am on my own. They are convinced there is nothing wrong with any of the suspension parts, control arms, ball joints tie rods etc... The only thing left to try is a different drive shaft and two different front tires. I will have to see what I can dig up.

[Steve Wood]

you can elevate the rear tires and prove the driveshaft good/bad as I suggested.

A quality shop with a roadforce balancer can prove the tires and wheels

[rhturbo]

So assuming everything that's been checked multiple times so far is not the problem (Ball joints, Control arms, tie rods, wheel bearings, shocks, springs) I am down to drive shaft or tires ?

[Steve Wood]

Personally, I would not assume anything, but, then, I guess my experience leads me to that...

[TexasT]

What are they using for camber and caster settings? Have you looked at the bushings? The pass side where the down pipe goes past is a common problem.

[rhturbo]

They say they have looked at everything.The y showed me the car on the hoist. Everything seems to be greased up nicely. I agree it does seem like it has to be related to something worn for it to shake that much. Will be a couple of weeks until I can report back again