Over the last year and a half I have been haunted by a vibration in my car. It all started when I changed to the 9" rear end.
We thought the vibration was caused by incorrect pinion angle. Reset angle. Nope
Maybe worn out leaf springs. Bought new ones. Nope
Maybe the tires were out of round. Checked that, a little bit out of round. Bought new tires. Nope
Homemade traction bars? Bought new Caltracs. Nope
Then the rear end started making noise. So, must be the rear end. Quick Performance sent me a new one. Nope
A couple of weeks ago, I put the car on stands, put it in gear and watched the driveshaft. Wobbled all over the place.
Thought I must have installed it wrong. Nope
Had Roger and my neighbor (life long Ford mechanic) come over and look at it, and both said it looks bad.
Did a check with a dial indicator and it showed the driveshaft was .070 out of balance.
Called Drivelines NW and he said it was impossible. Now get this........He said their quality assurance processes made sure they are perfect.
Well if you have followed this problem, you might remember that the first time they made the driveshaft they made it too long. Oops.
They remade it, but this time instead of cutting it 1 1/2" shorter, they cut it 3" too short. Oops.
So when he told me their inspection process makes them perfect, I reminded him of their imperfect production twice. Oops.
So...I took this driveshaft down to them, showed him the readings I got with the dial indicator. He said they would check it, but it is impossible for it to be that bad, because if it was, it would vibrate the windows out of my car. I said "Thanks a lot" that is what I have.
Now, before I took the driveshaft to them, my brother told me to put notches in the fittings so I could tell if they did anything.
Today, they said it was ready. When I got there, they told me that there was really nothing wrong, maybe a 4-6 thousandths off, and one missing washer.
But, what is weird? The notches weren't there. Also, the balance weights that were on it were rectangular. Now they are round. No evidence of them cutting the others off, no grinding.
So, instead of admitting they screwed up, they made up a story and made me a new driveshaft.
I installed that driveshaft today, and miracle. NO wobble.
I will drive it tomorrow if I can and see if the vibration is gone. I will update. Larry
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