Quote: The pinion will move from it's preset angle and it's relationship to the driveshaft.
Can you please explain as you understand it. mike
Not Mike, but will answer for him, there is no "as we understand it", it is what it is. The pinion does NOT maintain the same plane, through the arc of differential travel. Don't know any other way to explain it. The differential, does not stay stationary in one spot and simply move up and down. It SWINGS in an ARC. If it does this, the pinion can not possibly stay on the same plane. A 4-link is, to way over simplify here, nothing more than a long ladder bar. Properly set up, if you extended the upper and lower bars, they would eventually intersect. This is the "Instant Center" of a 4-link. The rear swings in an arc, from this instant center. Now where a ladder bar and 4-link differ, is that a ladder bar has a constant instant center, that being the front mounting point and a 4 link has a large amount of instant center combinations, depending on where you position the bars. Also, with the position of the brackets on the housing and the fact that the top and bottom bars are generally not the exact same length, the instant center of a 4-link is also constantly changing as the rear swings. I don't know of any other more clear way to try to explain it.
Monte
I would like to add for all Mopars cars with the engine and trans in the stock or near stock location that if the angle of the front u-joint is within the specified angle(working range)of the manufacture recommendations or negative of the trans output shaft NO CORRECTION is require.Pinion angle is measured at the rear u-joint and should be adjusted at the rear u-joint to insure it maintains a reasonable alignment within the working range.Many high powered,high torqued performance cars may need additional negative pinion angle at the rear u-joint to ensure that under power and torque loads a reasonable working range is achieved and maintained.The angle will constantly change as the power/torque is increased or decreased.Never change the angle of the front joint buy raising or lowering the trans unless it is beyond the specified working range.If you have to shim the trans mount excessively look for a problem at your rear suspension.This is from a design engineer that claims hands on development on the Luner Rover suspension.So this will hopefully help 85% of the people with mopars with stock style cars that run springs,4links and ladder bars with stock style front suspensions and engine/trans locations.Most the rest of us know how to build race cars or have some professional do it for us.In typical "Barnyard Fashion"85% can now Moooovvvee on with confidence and rest of us can do what we do,while "Chiken Little" can cry that the sky will fall if you don't do the front angle thingee.No Disrespect to any one,just relaying what some wizeazz engineer told me,you all know what I think about engineers
