| Message |
0) I had humming sound when accelerating and cabin vibration for speed only above 100mph
1) My transmission mount is OEM and 5 years old (it sags a bit but the rubber doesn't touch the metal yet)
2) I fitted a new center bearing few weeks ago, it's a CB70 for TT from Australian seller (CB70 on Ebay), my 300 is 2+2 TT
3) Then, I experienced some vibration in the rear of my seat when lightly accelerating from 40mph to 60mph and when cruising at these speeds, no vibration at all at high speed (good !). Randomly, the vibration may disappear, but the most often when the car is really warmed up.So, I decided to check again my driveline. Here is the outcome: z is the vertical axis (height)
y is the axis orthogonal to the centerline of the car
x is the axis parallel to the centerline of the car 1) I noticed the CB70 is not perfectly parallel to its mounting locations on y axis. I also noticed the CB70 bearing itself may have not the right position in the y axis to accomodate perfectly the fact the diff pinion is offsetted (diff is not symetric viewing from the top, and the transmission axis is offsetted too). All of this to tell the 2 pieces driveshaft is not perfectly straight on the x axis
3) Then I mesured the angles on the z axis : the CB70 (because it's new) is now the highest point on the z axis. The transmission is 1°54' lower than the CB and the diff pinion is 1°20' lower than the CB. Guys, what do you think about that ?
Should the 1st piece of the driveshaft be perfectly straight ? (0° angle b/w the CB and the transmission output ?)
I read this is common to have the diff pinion 1° lower than the CB to compensate the fact the diff raises a bit on load ?
|
 |
