How To Read A Differential Gear Pattern: A Beginner's Guide. ( Gear Tooth Contact Pattern )

[@RepairGeek]

Links to the tools required to rebuild a differential: Gear Marking Compound: amzn.to/4agE3Ek Calipers: amzn.to/48nlVr7 Dial Indicator: amzn.to/3utnAxB Beam Torque Wrench: amzn.to/3UODXzz Pinion Flange Holding Tool: amzn.to/3SZ2NLF Bearing Splitter: amzn.to/4bIN1f2 Bearing/Seal Drivers: amzn.to/3uCYrAs Hot Plate: amzn.to/3uuUu0Q Shim Drivers: amzn.to/48j5KLp Chemicals: Retaining Compound: amzn.to/3SZpbEI Thread Locker: amzn.to/48kF7pl RTV: amzn.to/3OLwaP9 Degreaser: amzn.to/3uBzhlG Parts used in this Ford 8.8 build: Ford Performance 4.10 Gears: amzn.to/49EJrRk Ford Performance Install Kit: amzn.to/3I3hR4w Torsen T2R Differential: amzn.to/3SKyXsQ Moser 31 spline Axles: amzn.to/3I4DYaI Crush Sleeve Eliminator Kit: amzn.to/49AKSAr My Amazon Store: www.amazon.com/shop/repairgeek Help support the channel, buy using my Amazon links As an Amazon Associate I earn from qualifying purchases and your cost is exactly the same.

[@jimmyfreeze3782]

This is the best gear pattern video you will find on youtube. Not sure why search fails to list this video at the top.

[@thinkingimpaired5663]

I appreciate your tutorial. Thanks.

[@MachRC9]

Excellent Video!! Thanks!

[@paulstefos2565]

Awesome explanation of how to do a diff setup...at least for those of us who have no idea. Thanks mate...keep up the great work!

[@mattritz5825]

Getting ready to re-gear my Dana 80 and Dana 60 to 4.11. This is one of the best videos I've found on gear patterns. Great job, man! Thanks!

[@jaimeoops]

The definitive guide is this.

[@kenrudd1073]

Awesome job my friend.

[@David-yy7lb]

Awsome explanation....I have Yukon 4.56 gears in my AM 11.5 differential when I ran the pattern my tooth contact on the ring gear was dam near identical to the pattern Yukon gear recommended pattern was not to deep or to high my backlash was .006 and that's been 200k+ miles ago with no noise in the differential

[@cecilandrews7479]

The reason for backlash being kept within the specifications. 8 being the tightest I would ever accept is because when you're driving the ring and pinion heat up in that backlash disappears. Two little backlash after the gears heat up puts the gear set in a major bind. Which will result in failure

[@JayJay-de8vq]

​@@cecilandrews7479I think it depends on if the geats are "2 cut" or "5 cut" gears for the backlash range.

[@saltymethods2637]

This is awesome. Thank you for this information.

[@fetus2280]

Very well done mate. Thank you.

[@steveschrader9250]

Great video for sure. I'm having my dif rebuilt here soon. I'll definitely go in knowing a lot more. Thank you.

[@msc1064]

Thank you this was a great video for the ring and pinion set up. I have an old 1993 Jeep Wrangler, and I plan on rebuilding the rear with everything. This video is exactly what I was looking for. Thanks again sir.

[@HumperMKB]

It’s a matter of “oh pinion” 😂

[@RepairGeek]

😂😂😂

[@michaelatkins9780]

If we were to do a paint pattern on that joke, I'm afraid we would find it slightly misaligned.

[@antonioorozco4896]

😂

[@Darren-zp5up]

"What's the diff? It's only a matter of a pinion, no real bearing on subject "...

[@Darren-zp5up]

That was a great explanation, A saying I learned was ... Face and Flank, move the crank(pinion). Toe and heel, move the wheel( crown wheel).😉

[@rice_219]

Thank you this was really useful. I have managed to achieve a pattern pretty much identical to your final one while nailing the backlash. This was on a diff for my 1977 Triumph Spitfire 1500. Really excited to hopefully have a nice quiet unit after all this time!

[@ikram3617]

Excellent

[@TheBFHGarage]

The BFH Garage has great videos on setting up gears including pattern interpretation.

[@w0rm37]

I just fully rebuilt my rear diff & my pattern looks just like this but other people are saying it's bad for the line to be so straight it needs to fade.. I was worried but im hoping nothing is wrong.. it was my first time & probably one of the hardest things I've done.. didn't know there was so much to go into a diff..

[@webstella]

What does it mean when you take the cover off and it looks like someone stuffed it full of steel wool? That diff ran fine up until I decided to change it out with a low mileage unit just incase. I discovered the "steel wool" inside at 160000km, cleaned it out and ran it till 330000km. Pinion ate deeply into ring gear during that first 160k. Pretty sure it came that way from factory, it was a one owner Jeep XJ Chrysler 8.25. Didn't even make noise.

[@alpeterson8126]

Excellent video!

[@norbertrivera]

Wow! i learn a lot with you,i wish to said thank you for share your videos and your knowledge.

[@bobbemoras9334]

Excellent explanation.

[@impactodelsurenterprise2440]

The machines to cut spiral bevel gears are insanely expensive and it takes a highly skilled and experienced machinist to cut it right.

[@FordTechMakuloco]

Nice!

[@brucelangereis6236]

Does the contact pattern change when under "significant" load on the gears? If yes should the pattern "without" load be set to adjust for movement to significant load?

[@theslimeylimey]

Why do you HAVE TO stay in the specified range for backlash? Isn't the mating pattern of the teeth far more important than a couple thou out of spec backlash?

[@cecilandrews7479]

Backlash is determined by how much heat the gears develop and expand. With two little backlash has the gears heat up will put the gears in a bind resulting in failure

[@gregsmithracing4479]

Avoid using terms like thicker/thinner pinion shims. On axles like 14 bolt/9” a thicker pinion shim does the opposite of say a Dana 60, try to use terms like move the pinion closer/further from the ring gear.

[@timberlinetraction943]

Extraordinary video my man!

[@bernardwarr4187]

Great. Information, many thanks

[@beadblaster9508]

Does tightening pinion depth,say .10 down to .06 create more gear noise. Also you do not see many people talk about carrier preload. Some people just wail away on the diff trying to get it as tight as possible and other is just about falls in. Some builders will use a case spreader to get in as many shims and get it as tight as possible. I am concerned mainly about try to stop gear whine. I am installing a set of 4:56 nitro gears in my colorado and they are notorious for being noisy. One person who got his set to be quiet was to get the pattern very close to the toe and get it center from crown to heel.What would you do to try and minimize the noise. Thanks

[@donboschman]

How do you pull inner pinion bearing on and off for shim changes without damaging bearing

[@shaffer4220]

I had a professional shop rebuild my GMC 8.6” all new. After 14 months the Eaton Tru Trac failed with clunking backlash (.460” backlash. Reading at 5” off centerline of axle). The new shop is going to reuse the Ring & Pinion but install a Dura Grip. I’m told he will tighten the pinion backlash to .006” (it was originally set at .010). The original wear pattern is perfect he says. Will that extra create noise???

[@BillyWillicker]

Yes.

[@edselbritting9792]

Excellent, thank you, i purchased spicer 4.88 gears to replace oem dana spicer 3.73 hopefully all goes well ... Ps. I remember you mentioned in another video when you disassembled the mustang rear that it had timken and koyo, i purchased yukon master overhaul kits and they both (front n rear jeep diffs) have timken and koyo on the pinion, after some research it appears (i may be wrong) that koyo bought out/ merged w a portion of timken business, from what i understand although Japanese company most of the differential koyo bearings are manufactured in usa ?

[@jimmyfreeze3782]

Pro tip- Use Koyo (USA or Japan) vs Timken. Don't believe me, put them side by side...you'll see.

[@cptdavidwebb]

Excellent video, Thank you.

[@dbarkley1053]

I need your opinion. Installing a new eaton trutrac with an existing ring gear. The ring gear just slides right on to the carrier. It has aboit .0001 of play. It's a dana 44 axle with dana gears. If I freeze the ring, then it's tight. It's that close of a fit. The ring gear fits the old carrier, and the gear didn't need to be hammered off, but it's tight. Send it or get a new ring and gear?

[@RepairGeek]

Call Eaton. I used a torsen in this car for a reason. The Eaton is made in Taiwan, Torsen is made in USA and they cost the same money.

[@paulnoone8103]

Where did you discuss the drive or coast side?

[@ChrisWilliams-pu8pj]

Great video. Thank you!

[@Personalized_Workshop]

Yikes! I pulled the carrier of a 12 bolt GM already without checking gear pattern first. The dealership diagnosed and recommended all bearing replacements to cure noise. That’s what we bought. Trusting they used a stethoscope. The noise was constant and didn’t increase with acceleration. If I don’t see that the carrier or pinion bearings have any defects, I’m not going to be so confident that the truck will be noise free after reassembly. Based on what you’re saying, I don’t have the original pattern to compare to and unless it looks really bad, I would just have to go with it.

[@Ronin6534]

If you are just changing the bearings just put everything back the same way.

[@Personalized_Workshop]

@ thank you, it worked out. Just had to use a spreader to get the left shim in.

[@CorkySandpiper]

What a great video!

[@ben2687]

Great video! One question..... I'm rebuilding an 8.8 as well and my gear pattern (drive side) looks good, coast is far to the toe, BUT I have 0.090 pinion shim!😮 I know this is way more than expected. Yes, it is a cheap hear set.....my bad.... I'm poor....should I be worried about the amount of pinion shim? Or just roll with it because the pattern is good? Thanks so much. This is my first rebuild.

[@Lolo7674]

Could you define "backlash" ?

[@justinhall5102]

Its the amount of play. If you hold the pinion so it wont move the backlash is the amount the ring gear moves.

[@tetrahydro_3653]

Great stuff! Thank you ...

[@hogeschoolgroningen]

Great Job!

[@edsnyder4073]

Great job, best video

[@RPMlegacy513]

Great video! QQ. I bought a used rear end, has an upgraded Eaton posi unit. Fits standard 98 chevy 2WD squarebody. It was not setup properly and when I checked the gear pattern it was way off, barely touching at all. If I try to rebuild it, new bearings, shims, redo backlash etc, will I have any issues with noise or performance?

[@RepairGeek]

You'll probably need a new gearset. :43

[@georgefromiami]

thanks excellent

[@mikec857]

My drive side is good thanks

[@xevvvi]

Hi could I possibly ask advice, is hammerite under body seal spray good stuff to use?

[@rferguson3719]

So if you have to take it apart by trial and error maybe 3-4 times to find the right pinion depth shim, won’t my inner pinion bearing get damaged from taking it on and off so many times with the hydraulic press and bearing separator?

[@RepairGeek]

Make a setup bearing. I address this in detail in the differential rebuild video.

[@rferguson3719]

@@RepairGeekyeah unfortunately either my setup bearings had enough difference in the tolerances, or a bearing race wasn’t fully seated. Cause my pattern changed from the setup bearing to final install with the bearings pressed on..

[@terryzak1742]

When I rebuilt my son's differential for his V6 Mustang, I purchase the "GXL Carrier & Pinion Bearing Puller Dana 30, 40, 60, 70, 80, Ford 10.25 Clamshell Design" bearing puller, which made removing the bearings very easy and didn't produce any damage. For installation, I finally had a good excuse to purchase a nice shop press. Great video. Really appreciate all of the insights.

[@cecilandrews7479]

Actually they have a clam tool to remove the bearings without damaging them. So if you don't do it for a living you don't need to waste money on a bearing set for setup

[@adiadrian1758]

Big big like !!!

[@davidcoombs1874]

I am putting 4.30 gears in my mustang GT. This video is helpful but I also had a laugh. See, there’s no state inspection where I live so I deleted the cats. I couldn’t hear the gears even if I wanted to lol.

[@stefansas4566]

Hi, I have a sprinter 519 with about 300k km, when I accelerate there is a sound in the differential, at the speed of 75-80 km/h it is louder. Who do you think would be the problem? (it seems to me that the backlash is higher than normal)

[@RepairGeek]

What does the fluid look like?

[@stefansas4566]

@@RepairGeek I changed the oil about 4k km ago, and it looked pretty good and there wasn't much dirt on the magneto.

[@RepairGeek]

If it has a carrier bearing check that first. Usually if you've had some kind of bearing failure in the differential you will have metal in the oil.

[@stefansas4566]

Today I looked through the filler hole and noticed that the backlash comes from the spider gear has play on the pin.

[@gabriela0612gh]

Thanks nice explanation I got now

[@user-pw7wl3nu1l]

What kind of rear end is that, limited sleep?

[@RepairGeek]

Torsen

[@user-pw7wl3nu1l]

@RepairGeek what does that mean? I have that on my 2013 Mustang GT. I'm going to rebuild it by watching your videos.🤝 Does this one have clutches inside?

[@RepairGeek]

​@@user-pw7wl3nu1lno clutches. Google torsen differentail for more info.

[@user-pw7wl3nu1l]

@@RepairGeek thank u!🤝

[@rickreese5794]

💯👍😎

[@VEN1]

convex = drive side. Concave =. coast side

[@jimfryar1]

Ok I’ll be the devil’s advocate, you didn’t explain how to adjust the backlash great video though, I learned a ton!

[@RepairGeek]

My rationalization was, if you are at the point of checking a pattern, you know how to set backlash. I also have a video that explains diff rebuilds in detail. I cover backlash extensively there.

[@arthurblennerhassett429]

"YOU" may have to take it apart 3 or 5 times.

[@RepairGeek]

Guys like you couldn't fix a headache with a Tylenol.

[@firstlast---]

​@@RepairGeek😂😂😂

[@michellebaxter1403]

Youre too high on crown. You should have space

[@Warrior_Resisting_Colonialism]

🤎👍🏾💪🏾🪶🦅