Help Check My Gear Pattern

[79vette]

Setting up a front 10 bolt with new 3.73 gears. I've never done this before, and appreciate any input you experts may have.

To me, the pattern looks well centered between the root and crown, centered between the heel and toe on the drive (convex) side, and slightly toward the toe on the coast (concave) side. Do you agree? Is this what I want?

[kwmech]

What is your backlash reading? If the backlash is good, I'd have no problem running it in the front. If this were a rear I'd take about 2-3 thou out of the pinion depth

[79vette]

Originally Posted by kwmech

What is your backlash reading? If the backlash is good, I'd have no problem running it in the front. If this were a rear I'd take about 2-3 thou out of the pinion depth

Backlash ranges from .006-.008" depending on where on the ring gear you measure. This is with a good mitutoyo indicator. The spec I have for a 10 bolt says .006-.010" is the allowable range.

Does it seem odd for the backlash to vary that much around the gear? Its almost like its not sitting flush on the carrier or something.

[mongocanfly]

What brand gears?...I wouldnt be suprised with some of the cheaper ones..
Did you clean the gears good before checking backlash?...
Like KW said..out front , I would run it..

[79vette]

Originally Posted by mongocanfly

What brand gears?...I wouldnt be suprised with some of the cheaper ones..

Literally the cheapest gears on eBay. I don't even know if they have a brand.
I cleaned the gears well before measuring the lash, but I didnt clean the gear surface super well before installing onto the carrier. I just wiped it with a clean cloth, but probably should have cleaned the gear and carrier with brake cleaner to get everything nice. I'll do that when I do the rear axle later this week.

This truck will probably be getting a dana 60/14 bolt in the next 3-5 years, so it doesn't need high dollar gears. But at the point I am in there doing work, I'm going to try to install my low-buck parts as right as I can.

I'm going to take 2-3 thousandths out of the pinion shim tomorrow as kwmech suggested and see what that does to the pattern, though I was thinking I would need to do the opposite (looked to me like the coast side pattern is shifted toward the toe of the gear).

[Getter-Done]

It looks good to me









.

[mongocanfly]

When he says take 2-3 out, it will move the contact patch more to the center of the tooth...
Notice how your contact pattern is more towards the inner side of the ring gear..
..keep in mind ,you'll also have to reshim the sides as well to move the carrier over..

[79vette]

Originally Posted by mongocanfly

When he says take 2-3 out, it will move the contact patch more to the center of the tooth...
Notice how your contact pattern is more towards the inner side of the ring gear..
..keep in mind ,you'll also have to reshim the sides as well to move the carrier over..

To clarify, I thought this is where think I am at. Contact pattern is shifted to the inside (toe?) on the convex (coast?) side of the gear. Am I misreading the diagram?
Thanks

[mongocanfly]

If you were building a 9in then you would use a thicker shim, as the thicker shim on it would move the pinion in the opposite direction from your 10in..
Where'd you get your pattern chart?
If you've got it that close, I'd leave it...its not that bad..
But This is different..

[kwmech]

Being a front axle I would leave it. That is unless you want to practice

[79vette]

I really do want to get this axle as close to "perfect" as I can, so when I do the rear this weekend I can get that one dialed in too.

I took ~0.004" out of the pinion and set the backlash at 0.008" again, and the pattern moved up toward the top of the tooth (I think this is expected?). Before I set it back how it was originally, I just wanted to verify that this pattern is worse than what I had initially. It seems too close to the top of the tooth.

I read another article on adjusting gears, and it does make sense that moving the pinion away from the ring gear centerline will move the contact patch up toward the top of the tooth. Am I just misunderstanding how this works, or do I need to go back the other way (add pinion shims to get the pattern back down into the center of the ring gear tooth)?
http://www.billavista.com/tech/Artic...ble/index.html




AFTER Adding 0.004" pinion shim:




BEFORE Adding 0.004" pinion shim (same pics from the top post):

[Getter-Done]

When I looked at the first picture I just glanced at it.

Now I see different pattern marks.

Is the Carrier itself / Running True?

It would be real easy to check now.








.

[79vette]

Ok, I think I got what I want now. I added back the .004" I removed, and added another .004" past that (bringing the pinion 0.004" closer to the ring than where it was in the original post). I think I am pretty happy with this pattern now, but if anything its still a bit high on the drive side. I am going to add another couple thou on the pinion and see if that gets it a bit better. If not I have these shim measurements written down so I can come back to it.

Backlash is at 0.0070"-0.0085" depending where you measure, and answering Getter-Done's question the carrier and ring gear runout are both within +/-0.0010" (measuring on the side of the gear where pictured, and measuring on the flat machined edge of the carrier just to the left of where the gear mounts.

[79vette]

Sorry, i have another dumb question. Does it matter which side the caliper brackets go on?

I got the passenger side together, but my driver side caliper has a little cast boss that is interfering with the mount bracket. One of the caliper brackets has "14023429" cast into it and the other has "14023430", but they look the same to me. I cant imagine what else would be causing the problem, but wanted to check before I go rip everything apart to swap the brackets.

I am usually a pretty good mechanic, but this job has absolutely kicked my butt... I have made every mistake possible to make and literally everything that can go wrong has up to this point, including now the brake caliper refusing to go back on the truck...

Thanks all for your help so far

[mongocanfly]

never mixed mine up so i dont know if theyll swap..
but a little googling shows
14023429 for left... http://oemcats.com/oem-parts/14023429.html
14023430 for right... http://oemcats.com/oem-parts/14023430.html

[79vette]

Well, I am 99% sure it would have worked fine with them swapped, but I took everything back apart and did it right.

Took it for a test drive, and the new 3.73 gears are what I wanted. I have a twin-sticked NP205, so I tried out the 3.73 in the front axle with the rear in neutral at the transfer case. Then I put the front in neutral and drove with the 4.56 in the rear to get a direct comparison (just dont put it into 4x4!). I am going to take it slow and easy on the new gears for 100 miles or so, but the highway drivability is going to be night and day.

Going to try to knock out the rear axle next weekend so I can have 4x4 again.

Thanks again for all the help with this axle build. It was my first time and I was a bit intimidated, but overall it wasn't that hard with some help.

[hjewell2]

sub

[79vette]

I did the rear axle this morning. It went much faster than the front, probably just due to luck...

The pattern looks good to me, but if anyone sees anything that looks weird let me know. This is a rear 12-bolt, backlash is at .007"

[mongocanfly]

Looks good..!!