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  • Ring&Pinion contact pattern verdict?

    I'be been working on my rear axle overhaul and I just thought I'd ask what the forum thinks of the ring & pinion contact pattern.

    I've tried many different shim combinations and this is as good as I was able to get it. This is with the original shim thickness.

    What do you think?

    This is already mounted on the car and the 2 test drives have not revealed any noises but the speed has been limited to about 45 mph.




  • #2
    Added som more pictures of the axle overhaul to a flickr album if anyone should be interested to see more...

    Ford 9" overhaul album on Flickr: https://flic.kr/s/aHskHiLiSY

    Comment


    • #3
      This is a job that I leave4 to my gear and axle guy for these reasons:
      • He has shims and left over parts from many jobs, so he can hit the pattern right on the nose.
      • He has the specialty tools like the long bar to hold the yolk while torqueing the 250-ft/lb nut. BTW, this nut requires the highest torque used in the entire car.
      • His facility is already set up for this kind of work.
      • He has done many hundreds of these so it won't take him very long. His time ends up costing very little because he is quick.


      Yes, I can do this myself but considering I will take a lot longer and I may spend more, it's worth it to me to pay my rear end guy. BTW, his work comes with a warranty. - Dave
      My latest project:
      CLICK HERE to see my custom hydraulic roller 390 FE build.

      "We've got to pause and ask ourselves: How much clean air do we need?"
      --Lee Iacocca

      Comment


      • #4
        Good for you!

        Originally posted by simplyconnected View Post
        This is a job that I leave4 to my gear and axle guy for these reasons:
        • He has shims and left over parts from many jobs, so he can hit the pattern right on the nose.
        • He has the specialty tools like the long bar to hold the yolk while torqueing the 250-ft/lb nut. BTW, this nut requires the highest torque used in the entire car.
        • His facility is already set up for this kind of work.
        • He has done many hundreds of these so it won't take him very long. His time ends up costing very little because he is quick.


        Yes, I can do this myself but considering I will take a lot longer and I may spend more, it's worth it to me to pay my rear end guy. BTW, his work comes with a warranty. - Dave

        Comment


        • #5
          One would generally be advised in the rebuilding process to return the ring & pinion relationship to the "as was" positions, not attempting to change from the familiarized wear patterns present. Hence, return the shim(s) as removed, for the purpose of the "pinion depth" relationship; and one should have measured the "back-lash" value prior to the disassembly, so as to know were to return this some to upon reassembly, controlled by the turning adjusters for the positioning of the carrier left & right.

          Resetting a used ring & pinion set (matched) in different housings, in other words fishing for the "right" set-up, requires more familiarity and understanding of the differential than that of starting with all new components. And if familiar with the subject, one can "cheat" some, to better excessively worn components, for better service.

          As far as your question, what do you think? The pattern as displayed seems to indicate that the pinion is too shallow in its' relationship to the ring gear. Meaning that less shim thickness would be required to move the pattern on the drive side inward from the heel of the tooth closer to the toe of the gear. the opposite effect would be realized on the coast side as appears wanting.

          But, don't go changing things because of comments made here! Differential set-ups are a hands-on, feel interpretation, and technique by the one directly involved, and although the pattern may not appear ideal, it may be as good as it gets, or was.

          Did you replace the pinion bearings & races within the pinion support? This is often a cause for an unintended change in the pinion depth, as one needs to ensure these components are seated upon their respective surfaces. And, if one isn't careful in not damaging the race seating surfaces within the casting upon the removal of the original units (poor technique with the hammer & drift!), the new units may not have established proper positioning.

          Also, if utilizing a "crush-sleeve" vs the solid spacer in the pinion assembly, note that these should not be reused under a second torquing (nor the nut), and the torque specification is NOT a value of just torquing the pinion nut to 250-ft/lb, but rather torquing the nut until a rotational "drag" experienced upon the rotation of the pinion gear within the pinion support is as desired, as measured in inch-lb resistance of rotation.

          Questions?

          Scott.

          Comment


          • #6
            Great stuff! I agree with everything you said.

            What might not have been clear from my initial post is that I also replaced the ring & pinion as the old set was worn down and the backlash was in a really sad place.
            So this is not a case of tearing it down and reinstalling the same gears.

            From looking at the old gears (2 first pictures in the flickr album I linked to above) it seems that the axle have been sitting for quite a while resulting in rust buildup on the face of the gears. (Documentation belonging to the car indicates that the axle was replaced with a used one so perhaps the axle sat a bit too long in a scrapyard somewhere)

            My own evaluation of the contact pattern is that it is in an ok place depth-wise but that I would have liked it more centered from heel to toe.
            The fact is that no matter what pinion depth I tried the contact pattern never moved much in ****-toe direction despite varying the backlash settings from tight to loose (within tolerances).

            My reason for posting my question here was more to see if I screwed it up big-time and the communitys reaction would be a "WOAA!! Dont drive that".
            I believe it is an ok pattern but as this is only my second time setting up an axle I thought it good to ask.

            Originally posted by pbf777 View Post
            One would generally be advised in the rebuilding process to return the ring & pinion relationship to the "as was" positions, not attempting to change from the familiarized wear patterns present. Hence, return the shim(s) as removed, for the purpose of the "pinion depth" relationship; and one should have measured the "back-lash" value prior to the disassembly, so as to know were to return this some to upon reassembly, controlled by the turning adjusters for the positioning of the carrier left & right.

            Resetting a used ring & pinion set (matched) in different housings, in other words fishing for the "right" set-up, requires more familiarity and understanding of the differential than that of starting with all new components. And if familiar with the subject, one can "cheat" some, to better excessively worn components, for better service.

            As far as your question, what do you think? The pattern as displayed seems to indicate that the pinion is too shallow in its' relationship to the ring gear. Meaning that less shim thickness would be required to move the pattern on the drive side inward from the heel of the tooth closer to the toe of the gear. the opposite effect would be realized on the coast side as appears wanting.

            But, don't go changing things because of comments made here! Differential set-ups are a hands-on, feel interpretation, and technique by the one directly involved, and although the pattern may not appear ideal, it may be as good as it gets, or was.

            Did you replace the pinion bearings & races within the pinion support? This is often a cause for an unintended change in the pinion depth, as one needs to ensure these components are seated upon their respective surfaces. And, if one isn't careful in not damaging the race seating surfaces within the casting upon the removal of the original units (poor technique with the hammer & drift!), the new units may not have established proper positioning.

            Also, if utilizing a "crush-sleeve" vs the solid spacer in the pinion assembly, note that these should not be reused under a second torquing (nor the nut), and the torque specification is NOT a value of just torquing the pinion nut to 250-ft/lb, but rather torquing the nut until a rotational "drag" experienced upon the rotation of the pinion gear within the pinion support is as desired, as measured in inch-lb resistance of rotation.

            Questions?

            Scott.

            Comment


            • #7
              First allow me to restate the following:

              Originally posted by pbf777 View Post

              But, don't go changing things because of comments made here! Differential set-ups are a hands-on, feel interpretation, and technique by the one directly involved, and although the pattern may not appear ideal, it may be as good as it gets, or was.
              Understanding the above, and my understanding that you are working with a new gear set (vs. used), if I were the one, I would want to see the pattern, particularly on the drive side, moved toward the toe of the gear more, with the resultant move of the coast side toward the heel some.

              Note that under load, the patterns both drive and coast, will move in the direction in which they are already bias in your example. This position migration is dependent on the some of the load and the allowed deflection at the relationship of the ring & pinion gears, due lack of rigidity in the support castings of the center section as a hole.

              This is one of the considerations for the gear installers' chosen "set-up", the environment in which the unit is to be subjected, and utilizing reasonable latitude to account for such in order to provide the best service.

              Scott.

              Comment


              • #8
                Rear end gear setup is extensively covered in the Service Manual, with examples. It needs to be done correctly. Nowhere in the manual will you find a pattern that is 'good enough'. Instead, they offer corrections until the exact pattern is attained. I urge you to follow the Ford manual because responsibility rests with you, not our opinions.

                I have done enough of these to know that an experienced rear end setup mechanic is required. I think you are posting here to find one but none of us can see or feel your work from behind a computer. Like most skills, we can talk about it all day but actually doing the job is quite a different story. An experienced rear end guy makes this job look easy. He is the guy you want to tag behind and learn from.

                At the factory, we assemble hundreds of these per shift with the same experienced and talented people who do nothing else. Yes, you can do the same work but the end result must be right or it won't last very long. Rear end parts are very expensive. We don't want to see you waste your money by having it fail or redoing this work. As said, the pattern is only part of this job. - Dave
                Attached Files
                My latest project:
                CLICK HERE to see my custom hydraulic roller 390 FE build.

                "We've got to pause and ask ourselves: How much clean air do we need?"
                --Lee Iacocca

                Comment


                • #9
                  In the document illustrating potential witness patterns one may encounter please note the terms utilized: "typical", but also not limited to, and "desirable", but also not necessarily attainable.

                  Although this illustration contains excellent informative guidance to ideal goals, if one has done enough of these, one will realize that the exact or desirable pattern may not prove achievable, if only due to the sometimes less than ideal manufacturing processes involved in the creation of the ring and pinion set relationship.

                  Hence my statement: "it may be as good as it gets"; and if reasonable, this often is "good enough".

                  Scott.
                  Last edited by pbf777; September 5th, 2018, 07:24 PM.

                  Comment


                  • #10
                    Originally posted by pbf777 View Post
                    Hence my statement: "it may be as good as it gets"; and if reasonable, this often is "good enough".

                    Scott.
                    I'd like to see the other patterns, with shims close on either side of the one used in pics, before I conceded that.
                    59-430-HT

                    Comment


                    • #11
                      When gears wear to the point where a correct pattern is impossible, it's time to pop for a new ring and pinion set.

                      I've seen gears worn to the point where the edges were sharp, like knives. That kind of wear is far beyond anything I want in my car.

                      I see 'good enough' in the electrical trade all the time but this applies to many applications: Just because it works doesn't make it right or safe.

                      A ring and pinion set costs around $225., in just about any ratio. That's cheap enough to make me shy away from a set that cannot be set correctly.

                      Many cars go to their graves wearing the same rear end lube that came with the car. Do yourself (and your bearings) a favor by changing rear end gear lube. Catch the old stuff and look at it in the sun before throwing it out. After seeing all those metal flakes glistening, I pulled the rear end open in our car and washed it out with kerosene and wiped it dry. The whole job only uses two quarts of 90W. - Dave
                      My latest project:
                      CLICK HERE to see my custom hydraulic roller 390 FE build.

                      "We've got to pause and ask ourselves: How much clean air do we need?"
                      --Lee Iacocca

                      Comment


                      • #12
                        Useless info.

                        Here in NZ a r&p set costs $400+ and you literally only get a ring-gear and pinion!

                        If made by Zoom etc it would cost even more.
                        A Thunderbirder from the Land of the Long White Cloud.

                        Comment


                        • #13
                          Rockauto.com offers several sets of Dana ring and pinion sets like this one for Squarebirds... US$156.79 (list price):
                          DANA 2020496 SVL One of our most popular parts
                          Rear; Ford Axle; with 3.50 Gear Ratio; with 9.00in Diameter Ring Gear

                          Yes Tom, it's only a ring gear and pinion gear in a matched set. I ran a 4.30:1 in my Mustang w/automatic OD. It pulled stumps and RPMs were still good at expressway speeds. - Dave
                          My latest project:
                          CLICK HERE to see my custom hydraulic roller 390 FE build.

                          "We've got to pause and ask ourselves: How much clean air do we need?"
                          --Lee Iacocca

                          Comment


                          • #14
                            To bad, DANA product that is manufactured in India. Probably a "buy-out" product, perhaps the same "stuff" as Yukon.

                            Scott.

                            Comment


                            • #15
                              Well, the R&P have been through its first 50 miles of break in and is working great. The whine that was there before is gone and Im a happy camper... Starting to enjoy my car again...

                              Future will tell if the contact pattern is good enough or not.

                              Comment

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