Got a break in the weather so I took the opportunity to measure and mess with some stuff. I measured the pinion stuff, and got this: transmission angles downward toward the rear at 3-4* (hard to tell exactly due to the measuring tools and all that, but figured this would be a good ballpark) The pinion is aimed downward and forward about 2-1/2-3*. So, if I am correct on figuring out pinion angle, I am around 1-1.5 (or as much as 0* if you use the two opposite extremes of my ranges) I am guessing negative. Before I left, I went ahead and rotated the drive shaft 180 (I know, poor experimentation to change 2 variables at once) and locked the nuts down just tight enough that the lock washers flattened out. Felt firm, but not "tight". It drove much better because of the 180 rotation. I have done this in the past and marked it before I took it off, but regardless of it being "wrong" now it lost the bulk of the vibration. Then I loosened up the preload on the Cal-Tracs and set it so the spring was just being contacted, and it still feels the same, maybe a little more vibration. It is silent when accellerating, quiet at high speeds above 60, and only seems to shudder at 50-60mph at cruise under load (when you keep your foot on the gas just enough to keep it there). It no longer does the wavering wuuaaahhh-wuuaahhh, but just vibrates a little. I wonder if i am just now feeling road vibrations through the stiffer floor and subframes?
Well, you got the 101 on pinion angle! Double check your u-joints, dropped bearings or any roughness. Good luck
Your pinion flange should point up toward the center of the car with the same degrees as the transmission points down toward the back of the car. If they both point down then you will have a big vibration that won't go away until you correct the angles.
If the transmission yoke slants down and back and the Differential yoke slants down and forward your driveline is hanging in a "U" shape and it cannot run true. It will continuously be trying to whip. That is what causes the vibration. Let put it this way: If you drew a line that fllowed the angle of your transmission output shaft and another line following the angle of the differentioal pinion shaft, they should be parallel. They should never cross in the middle of the car! Yes, to correct the problem you need to get wedge blocks to bring the angle of your pinion to match the angle of your transmission output shaft.
Have to disagree on this. Go back to article an go with that. Your rear will move up an that will "straighten out" your drive line. Pinion points down an will rise when driving forward. No disrespect Paul. But if I am reading you right, pinion point up is wrong. Maybe we are just misunderstanding here. Past post has a good tech line on pinion angle, see what ya think
Adjust your caltracs to give you about a 1deg up angle on the pinion in relation to where it is now when static,sounds like your cal tracs may still be limiting pinion movement a bit eventhough they are unloaded.It may take some time to dial this set up in.You are going to have to play around with it.PaulS is correct about the Paralell lines though.But:You have to raise the trans up not the pinion.Just shim it under the mount to gain a degree or so.Try adjusting your bars to get the pinion angle up a bit.If it dont work,then put it back where it was and raise the trannys tail shaft housing up via the mount.
Ideally you want your trans and pinion angles to be the same.Eg:3 deg down(-) angle on pinion equates to 3deg(+)up on the trans.Trans tunnel dimensions often dont allow for a lot of tail shaft adjustment up and down so you have to find a compromise that will allow for smooth operation if this is the case.
Yes, I understand now. My bad on the pointing. Long day no sleep and hard reading. Been under my car upside down too much also. The earlier article has the right angles posted as Paul has stated. (sorry Paul)Never dealt with the caltracs, only ladder bars, 4 links, an stock springs.
