Gear Set-up Pattern Feedback

[Mike_H]

I ran a few patterns tonight. Starting to get a feel for how things move and how one adjustment affects the others. I'm working on the front axle on my Rubicon and going to a 4.88 gearset. For what its worth, these are lightly used gears (less than 5000 miles).

I started at 0.061" pinion depth (factory) and had 0.007" backlash. Pattern was deep

I went with a big change to try and bracket my setting. So I ran a pattern at 0.050" Pinion Depth and 0.007" backlash. This is too shallow

OK...So I split the difference and ran one at 0.056" Pinion Depth and 0.005" backlash. This still looks deep to me

Final Pattern is at 0.053 Pinion Depth and 0.005" backlash.

I think this one is pretty decent. Couple questions though. I know I don't have enough preload on my carrier bearings. Its tight, but not "install with a hammer" tight." Will that change the set-up or can I add equal amounts of shim on both sides to bump up the preload and keep the pattern? The other is my backlash is kinda tight. Should I shoot for more like 0.007 since they are used gears?

Thanks!

 

[lBasket]

Idk much but I love following these threads

 

[hosejockey61]

I don't feel like you were ever shallow. But you are setting up used gears without a reference pattern to mimic so who knows....
I would have taken out another 3 thou on your second pattern you thought was shallow. As far as preload, since you are in the ballpark, tighten it up now and read the pattern as is.

 

[Mike_H]

I don't feel like you were ever shallow.

Really? I thought the pattern was running right off the face of the tooth. Can you tell me what you're seeing that I'm not?

 

[hosejockey61]

Really? I thought the pattern was running right off the face of the tooth. Can you tell me what you're seeing that I'm not?

The pattern isn't running off the face, it's running off the toe. The pattern needs to move up on the tooth towards topland. Open you backlash to 6-8 thou and see what you get. I think 3 thou will put you close. Go back to the pic in your other thread where you can see the pattern slightly without the paint all over it. That's what you'll want it to look like as that's the way they were broken in the first time.

 

[Mike_H]

I think I'm gonna run this. Got the backlash opened up to 0.009, same pinion depth and I installed 0.005 more shim on each side of the carrier bearings... It's pretty tight!

@hosejockey61 @Blackjack @NashvilleTJ @Wildman @someguysjeep

 

[Blackjack]

The pattern isn't running off the face, it's running off the toe. The pattern needs to move up on the tooth towards topland. Open you backlash to 6-8 thou and see what you get. I think 3 thou will put you close. Go back to the pic in your other thread where you can see the pattern slightly without the paint all over it. That's what you'll want it to look like as that's the way they were broken in the first time.

This. A lot of folks worry about the pattern being near the heal or toe but what really matters is that the pattern is centered from root to crown. For used gears you have to put the pattern as close to what it has already worn to or you risk gear whine.

 

[Blackjack]

I think I'm gonna run this. Got the backlash opened up to 0.009, same pinion depth and I installed 0.005 more shim on each side of the carrier bearings... It's pretty tight!

View attachment 318182View attachment 318183

@hosejockey61 @Blackjack @NashvilleTJ @Wildman @someguysjeep

I think you better run that.