Originally Posted by user151
Well I'm confused... in the last referenced link, centerline shows a mailburacing drawing and says it does not show pinion angle (he is correct, it shows pinion to driveshaft angle), but then he shows an Inand Empire drawing that shows the same thing!
What I gather is that the pinion and trans output shaft angles should be parallel (that is, equal but opposite sign angles) to eliminate vibration .... AND (here's the kicker) the U-joint angles should be 1 (min) to 3 (max) degrees to minimize U-joint wear.
Setting the former does not guarantee the latter... it would depend on how long your driveshaft is. Am I missing something? Can someone clarify this ror me?
You not only have a vertical displacement but also a lateral displacement of shafts centerline due to pinion offset slightly to one side of the vehicle.
The trans shaft centerline and the differential pinion centerlines should be parallel, theoretically, but in practicality the pinion angle points down 1 1/2 to 4* in static (non running) conditions because power load will cause rear suspension joint flex, or leaf spring twist. In such cases the theoretical centerline is zero under the anticipated load. It will not always be correct because load and suspension travel constantly vary.
The maximum joint angularity is 3* in any driving conditions.