9.76” Rear End

Jacksfan98 · March 16, 2019

Can any T1 non NHT owners confirm that the 9.76” rear end is installed on their truck if equipped with the 6.2L? It is stamped on the rear end by the yoke. My dealer has no idea? ? My 2016 AT 6.2L has the 9.76” but before I pull the trigger on a new AT4 I want to confirm the 6.2L still gets the 9.76” rear end. Thanks!

OnTheReel · March 16, 2019

I have NHT, but from everything I’ve read, all of the 3.23s are 9.5. They have two different suppliers, GM and AAM. Different RPO codes but both listed as 9.5.

MX86 · March 17, 2019

Only max trailer tow package gets the larger rear end

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Darksky · March 17, 2019

On the reel- you are mistaken in regards to the 323 gears being only in 9.5

My 2015 High Country has the 6.2 liter engine, the 8 speed trans and 3.23 gears in a 9.76” rear diff case. I am absolutely certain of this.

OnTheReel · March 17, 2019

That’s fine, but we aren’t talking about a 2015. This is the axle list for T1s.

8.6" axle 3.42 gear - 10-4091 / 19300457 High Efficiency 75W-85 (AAM)

9.5", Ratio RPO GU5 3.23 gear, Supplier RPO code SU7 - 10-4091 / 19300457 High Efficiency 75W-85 (AAM)

9.5", Ratio RPO GU5 3.23 gear, Supplier RPO code SU8 - 10-4122 / 19368514 Dexron Low Viscosity 75W-85 (GM)

9.5", Ratio RPO GU6 3.42 gear - 10-4091 / 19300457High Efficiency 75W-85 (AAM) - With 6 speed auto ONLY. WT/Custom/CustomTB.

9.76" rear axle 3.42 gear - 10-4091 / 19300457 High Efficiency 75W-85 (AAM)

*Note. Must ID the RPO codes to match proper fluids due to there being two different axle suppliers, GM and AAM.

Scooter Scott · March 17, 2019

This is a solid question because the K2 came with the larger axle if you got the 6.2L.

Bgctrading · March 18, 2019

Where's the stamp? I'll go look in my garage at my 19 6.2 non nht

Jacksfan98 · March 19, 2019

Directly straight back from the pinion yoke stamped on the casting.

Jacksfan98 · March 19, 2019

Here is the picture

Scooter Scott · March 19, 2019

So it does get the bigger axle??? That is badass

lt1z · March 19, 2019

That’s fine, but we aren’t talking about a 2015. This is the axle list for T1s.

8.6" axle 3.42 gear - 10-4091 / 19300457 High Efficiency 75W-85 (AAM)

9.5", Ratio RPO GU5 3.23 gear, Supplier RPO code SU7 - 10-4091 / 19300457 High Efficiency 75W-85 (AAM)

9.5", Ratio RPO GU5 3.23 gear, Supplier RPO code SU8 - 10-4122 / 19368514 Dexron Low Viscosity 75W-85 (GM)

9.5", Ratio RPO GU6 3.42 gear - 10-4091 / 19300457High Efficiency 75W-85 (AAM) - With 6 speed auto ONLY. WT/Custom/CustomTB.

9.76" rear axle 3.42 gear - 10-4091 / 19300457 High Efficiency 75W-85 (AAM)

*Note. Must ID the RPO codes to match proper fluids due to there being two different axle suppliers, GM and AAM.

This would seem to indicate that you only get the 9.76 with NHT which is the only V8 option that receives a 3.42 gear using the new engine and trans combos ( carry over AFM WT 5.3/A6 combos still get 3.42) Looks like all 3.23 trucks both 5.3/6.2 and A8/A10 get the 9.5” axle.

I don’t really see this as a problem though. 9.5” is plenty of ring gear for most

Bgctrading · March 19, 2019

I slid underneath mine couldn't see anything. I'll put it up on the lift after lunch.

Bgctrading · March 19, 2019

Mystery solved my truck is a 19 6.2 NOT a Max tow.

Darksky · March 19, 2019

I suspected this is how it would turn out. When I bought my truck, I was led to believe that the 6.2 liter trucks came with the 9.76. I can only be certain of mine.

if it still holds true - 3.73 is the largest gear that your 9.76 rear end will accommodate without changing back to a 9.5 carrier and an “adapter” bearing set.

Edited March 19, 2019 by Darksky