What RPO code for which transmission and gear ratio?

[KenBry]

When I bought my truck the dealer lost the window sticker and told me it was a 6 speed with 3.43 ratio. I want to be sure. Anyone know the RPO codes for which Transmission and gear ratios?

 

FWIW the replacment sticker is on the way to me from the dealer so I'll know for sure but was just wondering.

[Z45]

G80 Differential, heavy-duty locking rear

GT4 Rear axle, 3.73 ratio

GU4 Rear axle, 3.08 ratio

GU5 Rear axle, 3.23 ratio

GU6 Rear axle, 3.42 ratio

MYC Transmission, 6-speed automatic

M5U Transmission, 8-speed automatic

M5X Transmission, 8-speed automatic

[JimCost2014]

When I bought my truck the dealer lost the window sticker and told me it was a 6 speed with 3.43 ratio. I want to be sure. Anyone know the RPO codes for which Transmission and gear ratios?

FWIW the replacment sticker is on the way to me from the dealer so I'll know for sure but was just wondering.

Look in your glovebox for your build codes, and then match the post below yours for your trucks info.

[newdude]

MYC is the 6L80.

[njk4o5]

SUCK is for the 8 speed

SUCKIEST is for the 6 speed

[KenBry]

thanks folks, looks like I actually have a 8 speed and 3.42. GU6 & M5U

[KenBry]

SUCK is for the 8 speed

SUCKIEST is for the 6 speed

So none of the transmissions in these trucks are any good?

[njk4o5]

have you driven one? the trucks feel like they have a Toyota yaris engine in them until your foot goes 95% of the way down. the trans tuning in these are a joke

[KenBry]

Look in your glovebox for your build codes, and then match the post below yours for your trucks info.

Yep, thanks, I went to find all the RPO codes online but all the sites I found had out of date codes that didnt apply to most of the codes on my truck.

[KenBry]

have you driven one? the trucks feel like they have a Toyota yaris engine in them until your foot goes 95% of the way down. the trans tuning in these are a joke

Yes, I own one a 2017, no complaints even when towing.

[firecat_30]

i had a brand new 2015 denali with 6.2 and 8 speed and it was horrible.. converter wouldnt lock up it seemed in any gear and on highway the rpms would bounce up and down all the time and u could feel the truck surging.. i traded it for a denali duramax that i drove for a year and loved it. i now have a 2017 Denali with the 6.2 and 8 speed and it is awesome.. no more surging and shifts perfect. It is a little weird getting used to all the shifting though if your used to a 4/5/6 and havnt driven one yet but they are getting better and better. If u want a new truck with 8 speed go for a nice long test drive (15-20 miles) and see if u like it.

[JimCost2014]

Yes, I own one a 2017, no complaints even when towing.

Enjoy your new truck! Way more good ones on the road compared to ones with problems, just like all brands.

[WilliamBos]

On 5/4/2017 at 10:56 PM, elcamino said:

G80 Differential, heavy-duty locking rear

GT4 Rear axle, 3.73 ratio

GU4 Rear axle, 3.08 ratio

GU5 Rear axle, 3.23 ratio

GU6 Rear axle, 3.42 ratio

MYC Transmission, 6-speed automatic

M5U Transmission, 8-speed automatic

M5X Transmission, 8-speed automatic

Awesome info - thank you.