Help Choosing Rear End Gear Set

[D-n-Tyke]

When I swapped from 8-Lug to 5-Lug I found a used 1971 C10 rear end and put it in. She always had some gear whine but has now developed a bearing whine also. I always planned on changing the gears from the 3.07s in it to 3.73s so look like that time is now.

So my first question is which brand of gears are the better brand? What are people are having good luck with. I don't want junk. I have heard good things about Yukon gears, does that still hold true? What about Richmond?

Second question. When looking at kits on Summit I found these two kits. But I can't figure out what the difference between them is? Can anyone help me out?

Yukon P/N:YGK2227
Ring and Pinion Gears, GM 8.875 in. (12-bolt), Truck, 3.73:1 Ratio, 30-spline, Standard, Designed for Carrier Cases with A 3.73 and Up Gear Ratio, Kit https://www.summitracing.com/parts/y...ckup/year/1971

And

Yukon P.N: YGK2228
Ring and Pinion Complete Kit, 3.73:1 Ratio, 30-spline, Standard Rotation, GM 8.875 in., Rear, Kit https://www.summitracing.com/parts/y...ckup/year/1971

[Stocker]

Looking at Summit's website, the first one you posted, YGK2227, is for a 4-series carrier. YGK2228 is for a 3-series carrier.

[HO455]

I've spent a couple hours as of late shopping for a set of gears for the 8.5 in my Blazer.
Maybe my research will benefit you..

The concensus that I've found is that Dana/Spicer, OE GM, and Motive Gear in the Blue Box get the thumbs up from most people.

[D-n-Tyke]

Originally Posted by Stocker

Looking at Summit's website, the first one you posted, YGK2227, is for a 4-series carrier. YGK2228 is for a 3-series carrier.

So if my google research is right, since I am starting out with 3.07 gears I need to get a gear set designed for a 3-series carrier?

[Richard]

I used Yukon gears in the axle on my 94 when I switched to 3.73 from 3.42 after a failure. No problems after several thousand miles. Like about 2000-2200 rpm myself in final drive on a truck with overdrive. My custom high pinion D60 for the the 72 from East Coast Gear also has 5.13 Yukon gears. Purchased 5.13 Yukon gears from east coast along with an an ARB air locker for the AAM 11.5 axle retrofitted into the rear of my 72. Gears and air locker will be installed before I get the truck done.
If you have 3.07's currently you will need a need a new carrier or a thick gearset to go to 3.73's.

[HO455]

Originally Posted by Richard

If you have 3.07's currently you will need a need a new carrier or a thick gearset to go to 3.73's.

I went with the thick gear set when I went from 3.07's to 3.73's in my Burban. 50k plus and counting with no problems.

Does your rear end currently have posi? Or is that part of the change? I only ask as I have a open 3 series carrier in the garage I'd let go for shipping if your interested.

[D-n-Tyke]

No posi currently, and actually really not thinking of upgrading to one. She is a cruzer so can't really justify the cost of adding posi.

From what I am gathering I should currently have an open 3 series carrier in my rear end right?

[HO455]

The carrier to ring and pinion breaks are.

https://www.differentials.com/gm-8-8...t-truck-parts/

Carrier Breaks: 2.73 and Down;
2.76 - 3.42;
3.73 and Up

So with a 3.07 ring and pinion you have a 3 series carrier. To run a 3.73 you have 2 choices.
Replace the carrier with a 4 series carrier or,
Use a 3.73 thick gear with your current carrier. See link below.

https://www.ronsmachiningservice.net...lite-gear-set/

For what you have described I believe that most any popular brand would do what you desire as long as it was installed correctly. Here is a thread that has a post by someone who seems knowledgeable about the ring and pinion industry. Scroll to post #18.

https://www.pirate4x4.com/threads/da...gears.2472305/

[MikeB]

Excellent comments and advice above from HO455.

[D-n-Tyke]

Thanks for the link HO455. That was very informative.

Based in all this I think I will be looking to go with the Yukon 3.73 set that is designed for a 3 series carrier.

Now.... how difficult is this rebuild? I have all the tools just never dine it before so a little apprensive.

[MikeB]

Read everything you can. Here are just a couple of articles on the Internet. I expect there are dozens or even hundreds more on YouTube. Some of them actually helpful!

https://www.randysworldwide.com/web_...l_Complete.pdf

https://static.summitracing.com/glob...rp_install.pdf

Finding instructions specifically for GM 12-bolt truck would be most helpful, but 10-bolt setup is virtually identical.

[slikside]

As an aside…

Another potential source for diff parts is your local gear and axel shop.
I recently had mine looked over and a pinion seal replaced, and my old-school shop had TONS of very serviceable old metal rings, pinions posi’s,etc…
I didn’t need any of it, but for someone looking for a less expensive option, this could help.

[D-n-Tyke]

Originally Posted by slikside

As an aside…

Another potential source for diff parts is your local gear and axel shop.
I recently had mine looked over and a pinion seal replaced, and my old-school shop had TONS of very serviceable old metal rings, pinions posi’s,etc…
I didn’t need any of it, but for someone looking for a less expensive option, this could help.

That is a interesting thought I hadn't thought of. Mind naming the shop you were at? Might be worth a call or a drive by to talk with them.

[slikside]

Originally Posted by D-n-Tyke

That is a interesting thought I hadn't thought of. Mind naming the shop you were at? Might be worth a call or a drive by to talk with them.

San Diego Gear & Axel on Pioneer just south of Gillespie Field. Steve’s the owner and the guy to talk to. Cool guy, worth your time…

Funny, I didn’t notice you were local til you said you might drive by!Lol.

[LS short box]

The local mechanic that rebuilds my rear axle projects uses shims instead of the crush sleeve spacer to set the pinion pre-load.