Question regarding gear mesh point for rear diff

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by 02Rado373, Mar 14, 2017.

  1. 02Rado373

    02Rado373 New Member

    Hi guys I'm new here and trying to get some good information. I recently rebuilt my rear differential but and sort of confused on my gear mesh points. I feel like my gears run too far into the root but my buddy says it looks good! It also seems like I have a lot on contact compared to other pictures I've seen of people checking gear mesh. Last thing I want to be doing is tearing the rear end back apart after driving it for a bit. So here are some specs I got my rear pinion is shimmed at about .036. My back lash it between .007 and .009 which is correct for a 2002 silverado. It changes depending on which part of the gear I check it on. What are you guys thoughts? IMG_0615.JPG
  2. 02Rado373

    02Rado373 New Member

    Here is another pic IMG_0619.JPG
  3. silverado002

    silverado002 Rockstar 3 Years 1000 Posts

    There are some pictures on the web that shows different contact patterns. Google - "rear pinion gear mesh pictures". You will see quite a few pics.
  4. 02Rado373

    02Rado373 New Member

    Yeah not to be an ass but I have googled several images without getting a straight forward answer, which I am looking for here I'm basically asking if someone has good experience rebuilding these and if they would think the pattern is okay or if the pinion is too deep on the ring gear. This being the first differential I've ever done and it being done on my daily driver I like to make sure everything is okay.... I guess I will just pull everything tomorrow to try and get it to resemble the pics on google.
  5. silverado002

    silverado002 Rockstar 3 Years 1000 Posts

    I did the rear axle on my Chevelle with an Eaton posi and 3.53 gears. Based on your pics I think the pinion is a hair too deep and it tends to roll off toward the toe a bit. I think the pattern should be a little more oval shaped and centered more on the faces. Just my opinion.
    Last edited: Mar 14, 2017
    tbplus10 likes this.
  6. 02Rado373

    02Rado373 New Member

    Okay I appreciate that information I too was thinking it was a little deep... shimming for backlash is easy pinion depth though is a little more difficult but easily done as will I may have to pay for someone to remove my bearing now as it will take almost a week to get a decent puller to get at the rear pinion bearing.

    I thank you for your input
  7. silverado002

    silverado002 Rockstar 3 Years 1000 Posts

    Yeah I had all the tools which makes it much easier but I know what you are going thru. I bought the complete spacer kit and shims etc along with the new gear set. I replaced everything in that pumpkin and it worked out pretty good after the brain damage went away from checking and redoing etc. I hated that crush sleeve adjustment too.... :D:D:D
  8. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    Having rebuilt a variety of rear diffs I agree with Silverado002's input. Unfortunately getting a correct gear lash is a trial and error episode that can involve a lot of redoing what you've done before to get it correct. To get a precise and correct gear lash you have to do what almost amount to repetitive rebuilds of the diff.
    silverado002 likes this.
  9. j cat

    j cat Epic Member 5+ Years 1000 Posts

    backlash is good . the pattern is a bit off not by much . when checking the pattern load up the diff by putting on the park brake slightly that is how to get the correct indication.

    that pattern you show if it is with some loading on the diff do not mess with it its fine.
  10. Beachbourbon

    Beachbourbon Active Member 100 Posts

    Yeah, not to be an ass, but you should be less of one here. You're new and you're asking for free advice on something you screwed up on something you use daily.

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