Pinion and Ring Gear Contact Pattern

[Jeronimojc]

I am taking the Marauder back to the shop that installed 4.10s to address some installation issues. I haven't had noise issues but the contact pattern appears IMO requires moving the pinion closer to the ring gear, at least according to installation instructions for ford racing gears.

What do you guys think, do these pattern require an adjustment or are they okay? Since I don't have noise issues, I am only concerned abou the life of the gears.

http://www.mercurymarauder.net/forums/attachment.php?attachmentid=34 558&stc=1&d=1369957926

http://www.mercurymarauder.net/forums/attachment.php?attachmentid=34 559&stc=1&d=1369957926


Below is an image from Ford Racing on the pattern I think I have.

http://www.mercurymarauder.net/forums/attachment.php?attachmentid=34 561&stc=1&d=1369958504

Thanks,


Jeronimo

[fastblackmerc]

If the gears were installed wrong they would be noisey. I'd trust my installer.

[Jeronimojc]

Thanks. I don't really trust the installer, after I discovered other issues. Nevertheless, I get the point; the gears are not noisy, therefore they are ok.

[Blown3.8]

I agree with your view. That you should have a thicker pinion shim in. But if you aren't making a ton of power and they aren't noisy its ok.

[Baaad GN]

I think Justbob would eat them gears in a minute.

[lifespeed]

I believe the picture you have, and my memory from back when I did my own gear setup, says that the contact on the drive side is supposed to be more towards the outside edge (heel) of the ring gear. Under load, it "spreads" slightly towards the outside (heel) side of the ring gear.

I wouldn't put too much faith into the fact that it doesn't make noise today. Ring and pinion are supposed to be set up a certain way, and it appears yours is not quite correct. It looks like the pinion shim should be thicker.

I believe long-term wear and heavy loads handling would be adversely affected. Assuming you paid good money for a professional installation, they should fix it. It was a good idea to run your own pattern. Sadly, this does not speak well of the installer's attention to detail.

[lji372]

Shoot curless a pm. He knows how to MANipulate a rear end. He even had to redo a well known vendors work recently:eek:

Can't wait for him to get his hands on my rearend:bigcry: its gonna hurt


My pocket:D

[fastblackmerc]

I believe the picture you have, and my memory from back when I did my own gear setup, says that the contact on the drive side is supposed to be more towards the outside edge (heel) of the ring gear. Under load, it "spreads" slightly towards the outside (heel) side of the ring gear.

I wouldn't put too much faith into the fact that it doesn't make noise today. Ring and pinion are supposed to be set up a certain way, and it appears yours is not quite correct. It looks like the pinion shim should be thicker.

I believe long-term wear and heavy loads handling would be adversely affected. Assuming you paid good money for a professional installation, they should fix it. It was a good idea to run your own pattern. Sadly, this does not speak well of the installer's attention to detail.

It's been my experience if the rear doesn't make noise after the gears have been installed, they never make noise unless you have some type of failure.

[Jeronimojc]

I appreciate all the input guys. I'll discuss with the shop. They'll be opening the gearbox anyway to fix other issues, they seem to accept responsibility for. Asking the shop to improve the fit may not be a stretch. They seem to want to make things right. If they refuse to, then maybe I'll live with it. We'll see. I bought a solid spacer to replace the crush sleeve just in case. Thanks again!

[lji372]

I appreciate all the input guys. I'll discuss with the shop. They'll be opening the gearbox anyway to fix other issues, they seem to accept responsibility for. Asking the shop to improve the fit may not be a stretch. They seem to want to make things right. If they refuse to, then maybe I'll live with it. We'll see. I bought a solid spacer to replace the crush sleeve just in case. Thanks again!

that's awesome:D

[justbob]

I think Justbob would eat them gears in a minute.

Three minutes. :D


Self proclaimed Builder Of Badassery.

Buy it, Break it, Build it BETTER.
"Since 2004"

[Baaad GN]

OK three minutes, 2 to start the motor!

[tbone]

All I can say is that when they pulled my stock gears after 120,000 miles, they looked brand spanking new. No sign of wear whatsoever.

[Stranger in the Black Sedan]

From someone who has built a few 8.8 rears: Although prussian blue is not the correct marking compound to be reading gears, from what you posted, the pinion depth actually looks okay. The drive pattern being out on the heel and the coast pattern being in on the toe tells you that the backlash is a bit wide. Tightening the backlash will move the drive pattern in towards the toe and the coast pattern off the toe. Looks like you need less backlash but the pinion depth is fine. I have seen a lot worse.

[Jeronimojc]

Looks like you need less backlash but the pinion depth is fine.

Not to disagree, but to try to understand... Please see the third picture in post 1. Am I interpreting this the wrong way? I am a bit confused, though glad to know the situation is not really that bad. I did pay a professional to do the work. Thanks.

[Stranger in the Black Sedan]

First off, there are two ways of manufacturing ring and pinions, hobbing, and milling. Depending on which type of manufacturing method is used will greatly affect how the patterns move across the tooth as you change pinion depth and backlash. Ford OEM and Ford Racing gears are face hobbed, not face milled. The picture you posted appears to be guidelines for a face milled, not face hobbed, ring and pinion. You need to look at the pattern interpretation pictures for face hobbed gears - they are different than the pattern pictures for face milled gears.

See the "face hobbed" section here

http://www2.dana.com/pdf/5717.pdf

Look at option number four under face hobbed. That looks like what you have, and the recommendation, consistent with my initial remark, is decrease backlash, pinion depth correct. Your pattern is too far on the heel (drive) and toe(coast) but the depth is correct. To move the pattern off the heel on the drive side you decrease the backlash. This will also slightly bury the pattern deeper towards the root but it will primarily affect heel/toe location. The fact that the gears are not noisy confirms the setup is not that far off, it only takes a few thousandths error in pinion depth for gears to make quite a lot of noise. It just looks like you probably have around .012" backlash from those patterns, and you should be in the .008"-.010" range on new gears to get the pattern further in towards the toe on the drive side, so it spreads out evenly across the tooth under power.

[Jeronimojc]

The fact that the gears are not noisy confirms the setup is not that far off, it only takes a few thousandths error in pinion depth for gears to make quite a lot of noise. It just looks like you probably have around .012" backlash from those patterns, and you should be in the .008"-.010" range on new gears to get the pattern further in towards the toe on the drive side, so it spreads out evenly across the tooth under power.

Thank you for such a great explanation:bows:. I had come across the two different types of gears and thought the picture I included was from the Ford Racing Gears installation instructions. However, I need to double check everything and thanks to you, now I know how to. Now I also understand why the gears weren't making noise. Plus I am more comfortable discussing this with the shop. I'll be taking the car in tomorrow. :beer:

[Jeronimojc]

Stranger,
After double checking everything, I believe the Ford Racing installation instructions contain an error. I know that seems unlikely, but if I understand things correctly, the pattern interpretation drawings shown in the FR installation instructions match the face milling gear type, not the hobbing type. Check it out: http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-4209-8.pdf

Now, everything else I can find confirms what you said that FR gears are face hobbing, including a google book search (link below). It may be hard to tell, but the pictures in post #1 alone may be sufficient to conclude these are face hobbing gears. http://books.google.com/books?id=Cqb2F03eYtsC&pg=PA108&lpg=PA108&dq=%22face+hobbing%22+gears+ax le&source=bl&ots=E-h1Xyphh2&sig=3FPZytQh-PusZHZgVEMdTRbv9Gg&hl=en&sa=X&ei=RoyxUa-GC4adiAL8woHwDA&ved=0CG0Q6AEwCQ#v=onepage&q=%22face%20hobbing%22%20gears %20axle&f=true

Here's the Dana link which shows the pattern for both types (for others who may be researching this issue).
http://www2.dana.com/pdf/5717.pdf

Interesting stuff. Thanks again for the lesson. :burnout:

Jeronimo

[Stranger in the Black Sedan]

Sometimes literature isn't updated, I can't tell you why they have the old pictures. I see that many people incorrectly refer to face milling patterns when they really have the newer style face hobbed gears, and even service manuals reference them even when they aren't correct anymore.

Here is the pattern from the most recent 8.8 I set up (Ford Racing 4.10s in my own marauder)

http://bondospecial.smugmug.com/2003MercuryMarauder/Finished-rear-and-Heinous/i-B53vVxk/0/XL/DSCN4500-XL.jpg

http://bondospecial.smugmug.com/2003MercuryMarauder/Finished-rear-and-Heinous/i-33xcTRK/0/XL/DSCN4503-XL.jpg

[hotford]

Nice set looks bang on..........back lash 0.08-0.15 is the range prefered is 0.11
unless ford has changed their spec......

[Stranger in the Black Sedan]

.008-.012 is the published range, those patterns were run at .008. there is an updated detailed install sheet for the Ford Racing gears

http://www.fordracingparts.com/download/instructionsheets/FordInstShtM-4209-8.pdf

[Stranger in the Black Sedan]

Oh PS nice find on this link, it has great pictures and explanation of the difference between face hobbed and face milled gears.

http://books.google.com/books?id=Cqb2F03eYtsC&pg=PA108&lpg=PA108&dq=%22face+hobbing%22+gears+ax le&source=bl&ots=E-h1Xyphh2&sig=3FPZytQh-PusZHZgVEMdTRbv9Gg&hl=en&sa=X&ei=RoyxUa-GC4adiAL8woHwDA&ved=0CG0Q6AEwCQ#v=onepage&q=%22face%20hobbing%22%20gears %20axle&f=true

Yeah the Ford 8.8 oe gears haven't been face milled since at least the 1990's from my understanding, and the Ford Racing gears are oem gears so any Ford Racing gears people have been using in the past bunch of years have been face hobbed.