The shims in my truck had indentations that fit in that hole. I'll see If I took a picture of the shims to confirm it was on the thinner part.
I think otherwise, the axle should be symmetrical front to back.
You may need caster shims if the alignment shop says they're needed, or if driving it is too squirrelly without them.
[on edit] I didn't find a pic of the shims, but I did find one that shows the spring pad with that hole oriented toward the front (and the kingpin wedge bolt to the rear.)
If your shims have a hole in them in the center, that would be where the spring center bolt goes (and also in the hole in the center of the spring mount pad on the axle.)
I do believe that the kingpin wedge bolt hole is tapered or at least larger on the front than the back of the axle.
Last edited by klhansen; 03/19/2022 8:41 PM.
