Thread: Vibration problem solved

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This is not a debate on pinion angle but with help from the guys on here mine is fixed and some say up some say down. Sometimes I create problems trying to figure out why they work like they do. Here is my question and some of it may not mean anything but someone may can answer it. The vibration trouble was when my pinion was up. My trans at the bottom of the yoke to the floor is 6.0" rear at the bottom of the yoke is 8.500" pinion is down 2 1/2 degrees trans is down about 4 degrees if I put a gage on the drive shaft it pointing down 5 dose this even sound like it would work like it should? I don't have any problems just wandering.

without getting into any of your numbers/measurements---------pinion /driveline angles are angles of the pinion,driveshaft and transmission out put shaft to each other-NOT to the ground--------altho some of these can be measured and worked out , the angles to the mothr earth are irrelevant--------its the u-joint angles and also don't forget that that also includes sideways if you have engine or rear end offset from centerline------


AND---the thinking about the pinion angle changing on acceleration does happen, however, remember that the rear wheels/axle are on the ground and it is the movement of the chassis up/down that is the prominent motion that changes the angles-----

The advice from companies making driveline components is that if you extend a line through your transmission output shaft toward the rear, and another through your pinion shaft extending toward the front those two lines will be parallel. With the line of the driveshaft between the two lines, the angles from the two lines to the driveshaft will be equal and opposite, tranny down, pinion up. Dave Severson posted not too long back that for a leaf spring rear suspension, which tends to "wrap" a bit under power (pinion rising) he likes to bias in about two degrees of differential on the pinion so that it equals out driving down the road. That is, say the tranny to driveshaft angle is 3 degrees down, he'll want to see about one degree up tilt on the pinion static, measured from the pinion line to the driveshaft. There are a ton of drawings out there showing the proper relationship, like from Inland Empire - http://www.iedls.com/asp/admin/getFi...&TID=28&FN=PDF

https://www.youtube.com/watch?v=DDmz0tibVGM Good stuff!! Pete