Huck's daily - 2005 Z71 crewcab

[TotalyHucked]

Here's a video I took last night. I'm stretching my arm back to hold the phone over roughly where the bottom of the rear seats are (they're folded down so you can hear more). I'm rolling slow and then accelerate to roughly 20-25mph here and start playing with the throttle, you can hear it come and go.

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[legopnuematic]

I wonder if you ran into a “false positive” sort of situation.

Your early/initial setup(s) did not appear to be wildly off, visually at least.

Looking back at my notes from the 14b sf I did, started at .02, it was decent, went to .03 was clearly deep, went to .025 was still clearly deep, went all the way down to .015, was clearly shallow. I can recall exactly, but think ended up back at .02 as the final setup that provided the best pattern. I’ll dig up the pictures showing that.

Point I’m getting at here is that on that setup within ±.005 of the final setup showed clear shallow and deep patterns, so .01, whereas you have gone way farther than that and it really hasn’t gone clear shallow or deep if that makes sense.

Which is for me where the confusion begins. But what I’m not sure of, is if the relationship between the diameter and tooth counts of the ring and pinion make any significant impact on the “slope” or rate of change. For example does a 3.07 gear sets pattern move “faster” or slower with a .003 change in pinion depth than a 4.88, assuming everything else is good and backlash held as a constant. Or do is there no difference at all or one that’s small enough to be a non factor.

Just more thinking out loud than anything here.

 

[TotalyHucked]

All good points. Maybe 4.88s just move much slower/less with changes because of the thickness of the ring gear. That's probably why I kept chasing and ended up so far away from the "normal" range of pinion shims people tend to see setting these things up, I never had an "oh crap, that's too deep" or "oh crap that's too shallow" moment. It was always just a change, was never really a clear direction of the change. Granted not many people are putting such a deep gear in either. My buddy that does alot of these (usually 3.55-4.10) says 20s/30s is typically where he lands for the pinion shim. He's 2hrs away and his business is insanely busy right now or I would've already had him come help me.

My coworker was pretty adamant that he doesn't feel it's awful and to keep driving it and see what happens. He's done a handful of 10-bolts and several Mopar 8 3/4 or 8 1/4s over the years. I'm not sure I have a good feeling about doing that, so I think I'm gonna go back to that .029 setup (especially now that I know better about thinning the compound down and spinning it with a drill) and try again from there. I think I'd eventually adjusted to a .026 PS when I drove it the first time. Like I said when I drove that setup, it had a very light rotational sound that I now think was probably just the tight section of the ring gear, that I have now flipped 180*