I have installed a 4in kit. Welded perches and installed springs and everything has gone smoothly so far.
The question I have is, I want to avoid (if I can)grinding off the old and welding the new axle perches. I have read a little on shims or wedges and saw them on 4crawler.
With my dual case it looks to me like my current problem would be finding a shim.
The angle my pinion is at is 6 degrees. But it looks like the drive line angle is going to be more like 22 degrees.
so If i am calculating this correctly it looks like I am gonna need about 14 degrees, taking into effect the 2 degrees I want to keep.
14 degrees seems way to much to shim.
Am I looking at grinding and welding the new perches after all?

Depends on the type of driveshaft you are running. With that steep an angle, a CV shaft would work well. With tipping the pinion up, you need to account for the decrease in shaft angle as the pinion rise, see:
- http://www.4crawler.com/4x4/ForSale/Shims.shtml#FAQ1

So between 22 and 6 degrees is 16, less the 2 static is 14 as you noted. However, you'll see the shaft angle lessen 1 degree for every ~4 degrees of pinion up-tilt, so you are looking at maybe a 12 degree shim if going that way. Can make a 12 degree shim, it'll ne close to an inch thick in the center:
- http://www.4crawler.com/4x4/ForSale/Shims.shtml#Ordering

With that tall a shim, you might cut/re-weld the perches on, not sure how they are so far off now. Or was this the original perch, confusing as you mention welding on new perches and not wanting to cut off the old perches.

Or with a single cardan shaft, you may not need any shims, depending on the t-case flange angle.

Yea, this is with the original perches.
I see
I gotta do some more math to figure out the actual shim degree I need
If I can get away below 8 degrees than I think I will go for it. I have a CV shaft(or will).
If not then I will just have to get to work thats all.


I love your products BTW. It seems when I thik I have a good idea for a special part, you make them already.
Never had a "field failure" either, quality stuff.

Thanks for the tips, I really appreciate the advise.

If you are running U-joints, the general the rule of thumb is you want the diff to be at the same angle as the transmission, you don't want to tilt the pinion to be in line with the d-line.