Need some guidance bmorgil . Trying to set up this rear end axle . Got some pics of the pattern ,looks like I might have to go in with pinion gear some more . What you think ? Need a link to patterns if you have or a place to find em. First pic is the drive side ,looks to be hitting on the heel , there abouts. Second pic cost side , looks to be hitting toe end . Any comments would be helpful.
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Dr. Dana will be by shortly, but here is some helpful diagrams/explanations to setting up a ring and pinion. From your pictures, you are definitely in the ball park of being properly set. I would try one more shim to gain a touch more contact, to center the pattern on the ring gear tooth. Bmorgil is the master at the driveline, and we will see what he thinks on the matter.
https://www.yukongear.com/blogs/how-...ear-patterns_1
https://www.sierragear.com/different...-gear-pattern/
It can be very difficult to get a good pattern read on a used gear. That said you can get a good idea of tooth contact. First you need more load on the output so the pattern will print a little better. Once you have a good load on the gears, pay attention to the drive side. The coast is what it is. If there are complaints of coast noise, then worry about it.
In your photo the pinion is not deep enough. You need to look for a spot that is showing good contact as close to the middle of the gear tooth as possible. You will get the biggest pattern changes from the pinion position. Always start with the pinion position. If it was mine I would add about .020" on the pinion and try to move the contact pattern down into the tooth (providing the backlash is correct). The pattern will move forward on the pinion and deeper into the root as the pinion moves in towards the ring gear. The pattern will also move forward towards the toe of the pinion gear. It is normal to have a new gear set show the contact towards the toe. This is OK. The pattern will move back towards the heel and become more "full" as load increases. The more used the gears are the bigger the pattern will be. On well worn gears you may end up with the pattern covering the whole tooth. That's OK as long as the backlash is correct.
Try to get a pattern near the center of the gear tooth. Make sure to adjust backlash as you go. As the pinion gets closer to the ring gear backlash will decrease and it will change the pattern. The reverse is also true. As the backlash increases it will change the pattern. Stay with the pinion, adjusting the backlash as you go.
Setting up an axle is a bit of an art because if you can hit it in a couple of tries, you will save a lot of time and money. I have looked at a lot of patterns and adjusted till I could not move my arms anymore. It can be tough if you are chasing noise. Not so bad if you just need a good pattern that will last and not too noisy. The most difficult time I ever had was getting the high end "Lingenfelter" Corvettes in the late '90's to run quiet. In a Vette you sit almost on top of the differential. If it is slightly off on the ring and pinion pattern, you will hear it. Especially at high RPM. In a Jeep it just needs to be close. Contact in the middle of the tooth as best you can. Towards the toe of the pinion is OK. Try it again and lets see another pic Wulfie!
Addition: Here is something I use to help myself set these things up in a fairly quick manner, relatively speaking.
The top of the tooth, the "Top Land" will make a straight line in the gear pattern if it strikes the actual face of the tooth. You do not want the top of the tooth striking the face of the tooth and making that straight line. That is too far off. It will make noise and it will be weak and it will run hot. If I do not see that straight line, I am very tempted depending on the application, to let it go.
Look at Wulfies pic. You can see the straight line in the paint. It is the top of the tooth striking. That is why I am saying move it a bunch. It should swing down in and show you how close you were. It is either going to stop making that straight line, or it is going to make a straight line going the other way. A straight line the other way is a big clue you were close. Split the difference and things are going to hone in for you. Look at the actual photos gm provided. You can see the straight line in the "bad" pattern. Notice it is not there in the "good" pattern. Also notice they don't seem to care where the pattern is as long as it is near the middle and there is no straight line appearing at the top or the bottom of the tooth.
So there it is. Don't think I ever gave up that tip. If it doesn't make any sense, I seldom do.
If this is confusing, "fahget" about it! Haha, I would be glad to try to clarify or sketch it out. Now a day's the machining capabilities are such that you can set up a gear set quite a bit easier, and with tooling. The gear marking method is still a gold standard in my book if you know what you are looking for. It would be good to make sure we all can pass it on.
Tnx bmorgil , found good pics of correct contact and lil explanation how . Heres a good pictorial of building d 44 and useful tips ," DANA 44 pictorial build NAXJA " . I will trudge along need to get more bearings and inner pinion race to make the on and off for the set up .
Tnx gmwillys , I finally found good pic of ideal contact pattern . Plus bmorgil book on how . You guys have been very helpful. Found site that makes kits of the ring gear bearings and pinion race for easy on and off but for the 30 spline shaft
See, we can all learn a little bit more than we thought we knew. I live in a world where diffs make noise/sing. Failures are not common except the occasional haunting vibration. Our diffs, (four per vehicle) are hard mounted to the hull, so the noise reverberates through the chassis. In the days of Sportsman class dirt track racing, we would set up Ford third members with different gear ratios for the variety of different track lengths and conditions. Then we invested in quick change transmissions to where we could change out the gearing in minutes, in between heats. Long story short, as long as the ring and pinion where contacting in the center of the ring gear, we thought we were golden. We didn't look at sharp lines in the pattern, because noise didn't matter. I'll have to save this thread in the memory bank for future diff building.
In your case gm, those gears were not made to be quiet, just brutally strong. There is a lot to making a gear set quiet so a Cad owner doesn't complain. Strength isn't always the main criteria. The first introduction of a Dana IRS into a Corvette, was a proto-type modified fork lift axle. The initial ring and pinion was not quiet to say the least. That was long ago.
You have too curved surfaces that you are going to try to get to touch on their high spots for lack of a better explanation. The closer you get to that spot the quieter the gears will become and the more efficient. The gear design is such that there is a wiping action between the teeth as they mesh. You want to be right on that spot on the teeth where the contact is the best, to hit the sweet spot for everything. The gear set will still only be as quiet as its tooth profile and machining. Cheap gears can be impossible to get any pattern on.
Some more trial patterns , seems like I failed again to get the ideal pattern. Bmorgil suggested I go in ..02 on pinion did that now looks like went in to much. So going to come out .01 and run pattern again. Before I had not enough now too much so split it and maby Goldie Locks . The pics are not that great but appears in to deep. First pic coast side second drive , but its not very clear gonna try rag drag next time maby get better defined pattern. Bmorgil if I take .01 off the gear pinion side do I take .01 off the preload side ?
Did you really do .20 (2 tenths) or .020 (20 thousandth's)? The recommendation I read said .020.Originally Posted by Wulfie
Jeff
'51 CJ3A
'47 CJ2A
No lol. I meant 20 thousandth . .02 ! Sry my bad .
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