What degree shims to set pinion angle

[Jjcord2015]

I recently lifted my xj approx 5” and put a hack and tap sye on my 242 transfer case. My driveshaft angle is 17*, and my pinion angle is 8*. So if my math is correct, 17-8=9* difference. 9*-2*(for wrap under acceleration)= 7*. So I would order 6* shims? Does this sound correct?

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[RCP Phx]

The math isn't straight forward because the driveshaft and the pinion both change at the same time, I would try some 4* shims first and re-measure.

 

[RCP Phx]

I'll at they don't change at the same rate either. I've found 1.5x works pretty close!

 

[trippled]

I just reshimmed mine. Had to go with 6s. My drive shaft changed .5 degrees. Initially I was 18.5 and 9. After it was 18 and 15, which is perfect for me.

If it was mine I'd go 6 if your measurements are accurate. Make sure you get the steel shims that bolt thru the spring pack.

 

[Greenz]

I had to go with 6* shims after buying 4s. (I'm 4.5" w/242) Your lift will settle some and the thickness of the shim adds slight lift. My angle numbers were identical to yours.

If you're going off your numbers and opinions, 4s are more likely to not be enough vs 6 being closer to target.

 

[lazyxj]

Does the driveshaft have a double-cardin CV joint at the transfer case?

Have you checked the slip joint to see if it has enough inward travel left, when the rear suspension is fully compressed?

 

[Einulfr]

You actually add -2° to the 9° because you want the pinion below the center line, so that's a difference of 11°. 6° should be fine, just make sure you get steel ones as I've seen many aluminum ones crack and crumble away over time as they fall out in chunks.

 

[Jjcord2015]

So to update, used 6* steel shims. That put the driveshaft at 15* and the pinion at 15*. I am getting some slight vibes from the rear at higher speeds and when under acceleration, as confirmed by removing and driving w the front DS only. Is this ok or do I need to get the pinion a couple degrees lower than the DS? I do have 4* shims I bought just in case.

My other concern is the driveshaft is almost fully compressed while installed (see before and after photos)

Do I need to have this DS shortened about 1-1 1/2” ?

Keep in mind this is a mall crawler, not an off-road/Rock climber. Might see some light trails but for most part it’s a road vehicle.

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[RCP Phx]

The amount of "slip" doesn't look "horrible". As far as pinion angles go as I already said, but the 4* shims should put in the money!