Pinion angle

[kunar]

I'm getting ready to swap an explorer axle onto my truck. I got it up on stands and realised things aren't quite what I thought they should be. My pinion on my current axle is pointed up quite a bit more than I thought it would have been. I've got 4" lift leaves and no stock block. The springs have a wedge bolted to the bottom though.

So my question, the flange on the tcase and the flange on the pinion should be on parallel planes, correct? Should I just make my new axle fit right or should I try to figure out why this angle is so far out of whack first? I don't want this issue to come back and haunt me next time I change my rear suspension. I've thought about adding lift shackles but that would only throw the angle off even more. Should I pull off that wedge before I put the new axle in?

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[kunar]

i think ive decided that the main reason for stuff sitting the way it is is because of the wedge on the leaves. im gonna pull it off before i put the other axle in. shouldnt the spring pads on the axle sit mostly level with the ground once the axle is installed?

 

[RangerSVT]

In a theoretically correct world, your perches will sit flat against the leaves and you will have about 6* of pinion angle, or parallel pinion/driveshaft angle. The tcase end will be on an angle, and if you can find one,a double cardian joint is always better, if you don't already have one. The lift springs in combination with the shim/wedge and extended shackles (if you have them) will lead to the pinion angle you have. It's good practice to have about 1-1.5* lower pinion angle, so when under a load (acceleration) your pinion will be parallel to the driveshaft. If you plan on lifting the truck with shackles, I recommend getting the shackles and installing them prior to the axle swap so you can get the pinion angle adjusted where it needs to be...

SVT

 

[kunar]

i didnt have extended shackles when i took the pic, im installing them before i set up my new axle though. i also do not have a DC driveshaft. this truck is a supercab and has a one piece driveshaft.

i didnt think much about the axle moving under accel, so that extra degree or so makes sense. i dont understand what youre saying about the driveshaft being in parallel with the pinion though. on a DC setup, yes, you should have all of your angle in the front 2 joints (the DC joint) and have no angle in the rear joint. in a standard single u-joint setup, you should have an equal amount of angle in each joint, correct? pinion parallel to the tcase output?

does anybody else think i need to pull that wedge off before i set stuff up? its probably not that big of a deal, but i dont want this to come back to bite me in the ass next time i swap out springs or add a block or something.

 

[RangerSVT]

By parallel I mean in line. It's hard to adjust ujoint angle at the tcase, so the adjustment needs to be done via pinion angle. Since you will be welding on replacement perches, you can remove the wedge and adjust the perch to compensate. Like you said, install the lift shackle, install the perches without welding and have the vehicle weight on the axle. Then you can adjust the pinion angle. Once the angle is set, tack the perches in place on the four outer corners of the perch, then remove and burn them in...

SVT