CK5
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The headache build..

I'll give you some advice of a family friend who's a retired machinist that sets up rearend gears on the side for over 4 decades now for anything from drag cars and 4x4s to stock vehicles and even early 1900s stuff. I'd setup a few rearends over the years that have worked fine and not made noise, but he showed me a few things on my latest 9" setup that gave me a lot more confidence than just reading the manuals.

First, try using way less compound, you just barely need a film on there, on only the two faces, the rest just wastes it and makes a mess that's harder to cleanup and redo. Look at how little compound is on the sample pattern.

Second, brush it on perpendicular to the tooth, not parallel. Its easier to see the edges of the pattern this way.

Third, use a leather glove or something to apply significant resistance to the ring gear as you turn the pinion to make the pattern, then you only cross it once.

Those three things will make it easier to see the actual pattern.

As for the pattern, the teeth flex under load so you want to be as tight as you can (closer pinion) without being too tight. From what I see .018 is too loose, and .014 and .016 are both candidates. But what was the backlash set at on those two patterns? Are you keeping the backlash the same for all these patterns? To get a better idea of where the pattern center is at, I'd want to see .012 if I was doing it, then you know if .014 is closer or .016. My point is, if .012 looks further off than .018(the opposite of .020), then .016 is probably the best, but if .012 looks close (barely opposite of .016), then .014 will be a longer lasting setup than .016, even though .016 will probably work fine.
 
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Okay. So yes, I trying to keep the backlash the same for each picture.
I was kind of thinking of trying the .012 shim just to see its pattern.
 
I agree with Heaths recommendations on the pattern grease, I also used a leather belt to act as a brake on the pinion.
 
It's a Ferd 9" Eric, not a Dana or GM like we are used to.(less shims would make the 9 deeper yet)

After seeing all of them I would use .016 if it was mine. Normally you wouldn't of needed to see the .012 to pick between the .014 and the .016 but considering the the punishment you are going to give this axle with your engine you wanted the extra thoroughness. If you notice the .012 looks about as far off as the .020, just in opposite directions, so .016 is right in the middle.

I also probably wouldn't of tried the .012 if this was a Dana or a 12 bolt, because it would of been too much of a PITA, with a 9" , its pretty easy to change pinion depth without changing the pinion preload and pulling bearings, or even crawling under the car for that matter.
 
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Yeah, the 9" is much easier to set up than the Dana 44.
I goof off most of the evening away last night and then changed the shim and reset backlash within a matter of minutes. .
 
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