Check my pattern

[SmokingRocks]

I’m putting my 4.88’s in and I have two different patterns below I need your input on. Keep in mind these are used gears so it’s not going to be a perfect pattern.

I spent 4 hrs chasing it to this set up.

1) 0.050 pinion shim, 0.0078 back lash

I thought both sides of this pattern looked too close to the toe, also the coast pattern looked a bit deep.

so I ran the next pattern

2) 0.045 pinion shim, 0.007backlash

My buddy at slee said the first 0.050 shim pattern looked good but I feel like its too far down on the toe, and a bit deep.

the 0.045 pattern looks more centered which I like and he hasn’t seen this pattern yet, cuz he’s asleep. Thoughts?

 

[baldilocks]

The second one is better. Increasing backlash will move the pattern on both sides of the gear tooth toward the heel.

 

[Malleus]

I agree with your personal assessment. For a used pattern, that's about as good as you can expect (i.e., all spread out); you can move the pattern around all day, but the size isn't going to change, since it's a function of tooth wear. It's going to be noisy though.

 

[Railwelder93]

Looks ok to me.


*not an expert, but I set up diffs on my own junk and none have exploded yet.

 

[SmokingRocks]

The second one is better. Increasing backlash will move the pattern on both sides of the gear tooth toward the heel.

Yea, but I can only play with the backlash so much, I guess I can get it down closer to 0.006" but thats the bottom end of the spec with 0.008" being the top. The box was marked 0.008 by the previous installer (I was told these were installed and uninstalled by slee years ago) so I was shooting for about 0.008. Guess I can split the difference, just don't like the idea of getting it too tight.

Update from my buddy at Slee who has set hundreds of these up regarding the 2nd pattern with he .045 shim; "Drive is ok (slightly shallow), coast is shallow. The 0.050 looked better, I'd ship the 0.050 patterns all day for a used gear set"

I'm not going to second guess him since he's got way more experience than me at setting gears. If I had a bunch more time I could probably come up with a shim pack to get to like 0.048 but I think I'm just going to go back to the 0.050 and tighten up the BL a bit to get the pattern off the toe a bit more.

Thanks guys