12 bolt ring gear contact pattern help
 

Hey everyone looking for a little help setting up my ring and pinion.

65 c10
12 bolt
Richmond 3.42
All new timken bearings

Pics are of my starting point. I started with .030 under the pinion and .008 backlash.

Need to know where to go from here to get a good contact pattern. Thank you for any and all help.


I can only load one pic at a time for some reason I'll follow with the other side in just a moment

Re: 12 bolt right gear contact pattern help
 

Here is the other side

Re: 12 bolt ring gear contact pattern help
 

That looks really good to me. I would sew it up.

Re: 12 bolt ring gear contact pattern help
 

Looks pretty good to me also

Re: 12 bolt ring gear contact pattern help
 

I agree, that looks pretty good to me. However someone with more setup experience may have different input.

Re: 12 bolt ring gear contact pattern help
 

I thought I'd looked good but I wasn't sure. This was the first setup to get a starting point. I guess I got lucky first try. Thank you guys!

Re: 12 bolt ring gear contact pattern help
 

That does look pretty good . I would remove .002 from the shim and see what you get . I see a hard straight line at the bottom of the pattern on both sides which may mean it may be a little to deep . And then play with the B/L .007 to .009 and see what it looks like . I would try this before I buttoned it up to see if it improves some .

Also you have a slight round moon shape at the top of the pattern . This also suggest its a little deep . It would run like you have it ok . But I like to get the best I can .

Re: 12 bolt ring gear contact pattern help
 

Ill pull .002 from the pinion shim and post pics in a couple hours. I'm in no hurry to put the axle together so if I spend some time getting it as perfect as possible I don't mind.

Thank you for your input!

Re: 12 bolt ring gear contact pattern help
 

Loos decent to me.

You can load more than one pic in a single post. Just load them one at a time in the same post.

Gary

Re: 12 bolt ring gear contact pattern help
 

Still only letting me upload one pic at a time not sure why...

I pulled .002 from the pinion and backlash is not at .007. I liked the first pattern better but I'm still learning the contact patterns.

Re: 12 bolt ring gear contact pattern help
 

Here's the other side

Re: 12 bolt ring gear contact pattern help
 

Looks as if the drive side is better . You lost that hard line at the bottom . It also looks like it has centered the pattern from heal to toe and top to root on the drive side . Has that soft pattern all around with out hard lines . The coast side looks pretty good as well . Your roll pattern is a little soft . Re roll and get some pressure on the ring gear so the pattern would be more pronounced and re post .

Re: 12 bolt ring gear contact pattern help
 

Here are the pics you requested...

Re: 12 bolt ring gear contact pattern help
 

And the other side...

Re: 12 bolt ring gear contact pattern help
 

In my opinion , that looks really good . I would run that . Good even pattern top to bottom , smooth lines , pattern center coast and drive side . I would run it .

Check your back lash 3 places . If you average .007 to .008 you should be good .

Some aftermarket gears can be a bear to set up . Unfortunately there are no oem gears out there for the 12 bolt . Gm quit making them years ago . AAM makes gm oem gears now and do not have 12 bolt gears . The Richmond orange box gears are not known for being quiet . It is a hit and miss . 3.42 gears are not as bad as the 4.11 and up .

Re: 12 bolt ring gear contact pattern help
 

Thank you very much for your help! It's greatly appreciated!

Re: 12 bolt ring gear contact pattern help
 

What do you guys think about this pattern? More pinion shim?

Re: 12 bolt ring gear contact pattern help
 

Still on setup bearings. Backlash at .008. I think I’m going with a pinion spacer instead of crush sleeve.

Re: 12 bolt ring gear contact pattern help
 

I was editing my post to show pics and somehow deleted it... the pattern looks good...id try it...but keep in mind things change when you swap out the setup bearings...crush sleeve eliminator is a good choice but will require more setup

Re: 12 bolt ring gear contact pattern help
 

Thanks Mongo. Looked pretty close to me but this is my first attempt at a diff setup. Based on the pics above, a little adjustment makes a big difference.

Re: 12 bolt ring gear contact pattern help
 

yep...just swapping out the bearing can change it all..it did on mine

Re: 12 bolt ring gear contact pattern help
 

Hopefully it won't change too much. I bought a new pinion bearing for setup. I bent the cage on the old one getting it pressed off.

I don't think anyone has been in this diff before. Looks pretty dang good for 50 years old. The backlash was loose and it wasn't posi so I decided to tear into it.