Dana 44 Front Axle Differential Bearing Shim Question

Discussion in 'General IH Tech' started by James Ruth, Oct 21, 2017.


  1. James Ruth

    James Ruth Farmall Cub

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    George, thank you for the encouragement!!! Yes this is good for my son. He wants to be an automotive engineer, so I invested in his future by purchasing all the tools and we are working through it together. Many lessons here: patience, perseverance, experimentation, creativity, improvisation, etc. Stuff you don't learn in school.
    The same for me!
     
  2. winchested

    winchested Binder Driver

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    Good way to start an engineer to. Most engineers have never touched a tool in their life and make life terrible for those that actually have to fix things.

    Not just automotive but industrial is far worse.
     
  3. James Ruth

    James Ruth Farmall Cub

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    OK, after weeks of deliberation and experimentation, I am back!

    My son and I have gone through the paces on this, being very deliberate. I think we almost have this.....we are so close. So I am enclosing pictures of the ring and pinion pattern we are getting. We would appreciate feedback on where we are right now.

    My gut is that we are in the ball park, as we have gone through many configurations to get here. Since it is a used ring and pinion, I think I am not going to get a perfect pattern. There is almost no backlash on the ring and pinion, turning the ring against the pinion is smooth. The case spreader was invaluable as was the Yukon clam shell bearing puller. Note, we are still using the dummy carrier bearings, but the pinion bearings are set.

    Main question is, given the pattern, does the pinion need to be closer to the ring?

    Secondly, when measuring the pinion backlash, is it done with or without the carrier / ring installed?

    Thanks for the help!

    James

    [​IMG]
     

    Attached Files:

  4. Darrel

    Darrel High Wheeler

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    Do you have a dial indicator? Patterns are only valid if the backlash is within spec.
    Every time you move the pinion in or out you'll need to get the backlash within spec again before running another pattern.
    The pattern does look shallow though.
    While you have your dial indicator out check the run out on your ring gear.

    Random video.

     
    Last edited: Dec 9, 2017
  5. James Ruth

    James Ruth Farmall Cub

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    I do have a dial indicator. I checked and the backlash is virtually nill. However everything turns smoothly like I would expect.

    I agree it is shallow, but what I read, even in the Yukon manual, you are not going to get perfect with used parts.

    Thank you so much for the feedback. I will give the pinion another hundreths of an inch and see where the pattern falls.

    Conceptually, I think I'm really getting the hang of how this all goes together. Thank you for all the help!
     
  6. Darrel

    Darrel High Wheeler

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    Nil won't work. When it heats up it will burn up.

    You need space for metal expansion.
     
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  7. winchested

    winchested Binder Driver

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    Ya I'd say you want more backlash on a used set then brand new.
     
  8. Greg R

    Greg R Y-Block King

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    This is true. New specs were .004-.009" I've found .009-.012" okay and not too noisy on old gears; though I prefer hanging close to where I found it before disassembly. What you don't want to do is this, though a bit exaggerated it does tell why new specs on old gears do not work:
    img015.jpg

    I think the pattern has too much toe. All in all I think the work these guys are doing is excellent!! This one last hurdle and they'll have quiet long lasting gears.
     
    Last edited: Dec 7, 2017
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  9. Bob BMW

    Bob BMW Farmall Cub

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    What Darrel and Winchested say about backlash is true. You got to have it. Just because it runs smooth the way you have it now doesn't make it right. Plus move the pinion closer to the ring gear by .002 to .003 inch to move the pattern down from the top of the ring gear tooth. Then adjust the carrier bearing shims to give at least .005 backlash. If you don't move the pinion closer now, when you give yourself some backlash, the pattern will be even higher on the ring gear.

    You are getting there!

    Bob
     
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  10. walkersscout

    walkersscout Binder Driver

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    Since you've come this far, and made the mistake stake of not keeping track of shims, do yourself a favor and buy a new set of gears. The old gears have given their life to teach you some lessons, now retire them, use those lessons to get a perfect pattern and backlash on a new set where you can actually get good forward and reverse patterns.
     
  11. George Womack

    George Womack High Wheeler

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    No such thing as pinion backlash. The pinion is set up with some preload, no end play. Backlash is clearance between the two gears, so yes, they both need to be installed to check it.
     
  12. 72soa

    72soa Binder Driver

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    I say run it. It will give you years of trouble free use in the front end. With the used gears it is really hard to get a good contact pattern. You can just get close. I messed with the used gears in my scout for hours. Could not get the right contact pattern. I did the best I could and put it back together. It has been years with no issues and lots of off road miles. At the factory in a mass produced environment I can't help to think the gears are set up that close as to what is represented in the manuals. They are cranking out so many axles how do they get all of those shims right? Oh. Sand, mud, goop in the front end is from 4 wheeling in the mud and water. Please replace your inboard seals as well.
     
  13. BigRigg

    BigRigg High Wheeler

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    I'm extremely late to the party. I've done a few gear sets, and I don't really have anything to add to the discussion. The reason I'm chiming in; I'd love to see the videos in this thread embedded (or whatever the correct term is...so they never disappear from bp), and this thread to be added to the faq's for gear rebuilding.

    This is one of the best tech threads I've seen here in quite a while. There is some really great info here, and this thread should be easy to get to in the future.
     
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  14. Darrel

    Darrel High Wheeler

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    It's not the pattern we're concerned about, but the zero backlash. Zero backlash creates excess heat, which results in metal expansion, which creates even more heat and more expansion, and so on.

    I agree completely that the pattern isn't going to be perfect. Even with new gears you won't necessarily get a text book perfect pattern. The best we can do sometimes is a compromise between too shallow or too deep. The pattern running off the side of a tooth (land, heel, toe) is a no-go obviously.
     
  15. James Ruth

    James Ruth Farmall Cub

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    Thank for all the great feedback!!!

    We worked a couple of hours on this today and got to a couple of configurations within spec.

    These are pictures of the pattern based on a backlash ranging from .009" to .012", taken at 4 different spots on the ring gear as outlined in the service manual.:

    20171209_161819.jpg

    20171209_161838.jpg

    We were not happy with that, so I decreased the backlash to .006" - .009" in order to move the pattern more toward the center as described in the video earlier in this post, thanks to Darrel! Here's what we ended up with:

    20171209_163127.jpg

    20171209_163136.jpg

    20171209_163201.jpg

    20171209_163210.jpg


    Looking at the patterns in the Yukon manual, this looks pretty good to me, although I am no expert. I am posting for final feedback.

    Since this is a front axle, and we are making a daily driver, I am inclined to go with this configuration. I will note that I am still using the dummy carrier bearings. I'm sure specs will change a bit when I press on the real bearings. Given that may be the case, would it be better to go with more backlash or less backlash?

    Thanks to all for their input. This has been a great learning experience indeed!!!
     
  16. Greg R

    Greg R Y-Block King

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    I agree you have a nice pattern. I think it's a bit much on the toe, but it is an opinion. For my work I would move the pinion back about .005", then adjust for backlash moving the carrier over. Are you putting resistance on the carrier to make the gears work? That will closely approximate real life and may shift the pattern a bit to a more real position. You may find it's good right there. I'm not striving for perfection, just long life as strength is more centered than at edges. Great work so far!!!
     
  17. James Ruth

    James Ruth Farmall Cub

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    Greg R,

    When you say you would move the pinion back, do you mean back towards the axle or back away from the axle?
     
  18. James Ruth

    James Ruth Farmall Cub

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    Also, I am using tension from the carrier preload @ 60 lbs torque
     
  19. walkersscout

    walkersscout Binder Driver

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    60 pounds of carrier preload? Might want to recheck that figure.
     
  20. Bob BMW

    Bob BMW Farmall Cub

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    I am pretty sure Greg means the pinion is too close to the ring gear now. That is why the contact pattern is close to the base of the gear. You previously had it too far away so the pattern was close to the top of the gear. Do you remember how much closer you moved it? I am talking about the pictures you showed when you had nil backlash and the last set of pictures you show with some backlash. How much did you change the pinion shim pack between these two sets of pictures?

    Since you are close now, why not swap out the setup bearings? Then you will see what needs to be done, if anything, to get to a stopping point.

    I like to put tension on the ring gear by wedging and holding a piece of wood between the ring gear and differential case. Really bear down on the wood while rolling the contact pattern. As you can see, this is not carrier bearing preload. I have never measured the preload but 60 foot pounds sounds like a lot.
     

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