[Oilbrnr]

Originally Posted by 84 400

I talked with kurt about this before ordering. The kit was designed to work with out the need for perch rotation and or a cv.

There is nothing about Kurt's or ORD's flip that has any inherent 'design' to maintain proper pinon angle. Think about it, the front eyelet of the spring remains fixed, all you are doing with the flip is moving the rear eyelet down X inches. As you do this the pinion starts to point up directly at the TC. Unless you drop the TC the same amount that you raised the pinion, you will induce rotational speed osculations that result in vibration.

With the OEM rear springs and a zero rate on my K5 the pinon pointed almost DIRECTLY (1-2* negative) at the TC, with the new Tuff Country 2" rears and no zero rates that I just installed last week it is now a straight shot to the TC yoke. This isn't great either, as the rear Spicer now does not have to 'bend' which means grease does not redistribute in the cups. Ideally there should be a 2* negative pinon angle with a CV. None the less, I'd rather deal with greasing the rear U-joint vs. putting up with the vibration and wear/tear on the output section of the NP205.

Might want to google 'driveline angle' and do some research and compare/measure your setup. I'd be willing to bet money you have issues.