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Hack N' Tap Installed......Shim Questions

Achmed

NAXJA Forum User
Location
Southeast US
I installed my Hack N'Tap tonight and it went without a hitch. Ok, here's the question. I get a small bit of vibration only under load at 60-65mph. At coast, it disappears. I am currently running 3* rear shims. My driveshaft angle is 17.5* and my pinion is pointing 2* higher (15*) than the shaft tube. Obviously, I need to re-shim to a lesser degree to bring pinion angle down. When taking out shims, I seem to think for every degree of shim I remove, it will actually change the difference in the pinion/shaft relationship by 2* because you are decreasing each item by 1* and summing the 2 differences at the point of angle junction.

If my calculations are correct, if I drop down to a 1* shim, I will actually be running my pinion at 1.5* under the shaft angle which is about perfect. Does this sound right? If not, what shims do you think I need?

What are your thoughts?

Thanks,
Chris
 
OK, maybe i am missing something lol.your actual pinion angle with the shim installed is 15* and your actual D/S angle is 17.5? i am not being a wiseazz just asking ok!
 
Here. Maybe I have the angle finder clocked wrong, but you get my drift.

ANGLES.jpg
 
How would you know what shim you need unless you use a angle finder? to many variables. stock shackles don't force your pinion angle up much at all. on the other hand, 1.5" lift shackles make your pinion point up quite a bit more.
 
Achmed i understand the pic lol. read your opening statement regarding both of your angle findings. you stated pinion was 15* with the shim installed and 17.5* on D/S. according to those figures your pinion is 2.5* lower. now if your D/S was 15* and pinion was 17.5* then yes you would be high on pinon. i am only reading the figures you typed ok.
 
How would you know what shim you need unless you use a angle finder? to many variables. stock shackles don't force your pinion angle up much at all. on the other hand, 1.5" lift shackles make your pinion point up quite a bit more.

Did you read my first post? I did use an angle finder. I'm not looking for a sermon, I am looking for technical reference on what removing 1 degree of shim does to pinion angle vs shaft angle.
 
Achmed i understand the pic lol. read your opening statement regarding both of your angle findings. you stated pinion was 15* with the shim installed and 17.5* on D/S. according to those figures your pinion is 2.5* lower. now if your D/S was 15* and pinion was 17.5* then yes you would be high on pinon. i am only reading the figures you typed ok.
Yeah Yeah Yeah. Angle measurement is all determined by what side of the angle you are one.
 
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