Don't buy a 2008 as they were not in those trucks. Buy a 2010 up CC or E. Cab with 5.3L engine as the six-speed automatic transmission was made standard. Not sure about Reg cabs but I think they were 6-sp also 2010+

2007 up Denali had the 6sp 6L80

Trans is not coded on the VIN.

Shifter looks the same until the engine is on.

Here is what the 6-sp dash reads, note "PRNDM", M stands for Manual shifting of the 6 sp. key on to see this. This is dash of 2010 GMC Sierra E cab

 

In 2010 anything with a 5.3, and up, had the 6 speed behind it. Only the 4.3 and 4.8's had the 4 speeds from 2010 on...
Before that only the Denali's and Vortec Maxx's had the 6 speed... And even then I think that was only 2009 maybe 2008...

 

I'm gonna go out on a limb here but isn't there a big difference between 4 and 6 speed ?

A 6 speed has a up and down shifting button on the column shifter

The 4 speed does not (4L60).

 

^^^^^yes you are correct the 6spd has a +\- button on the shifter. The four speeds came on the 4.8 v8 and other models. Also look on the window sticker should say four or six speed. There is a driving difference for sure. The six speed takes some getting used to.

 

The 6 speed also came in some 09s. Mine is a 2009 cc and has the 6 speed in it.

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Did I hear correct in that the vortec max had a 6 speed?

A few months ago I was looking at a 2007 nnbs with the 6.0L VortecMax engine and it didn't have the manual tapshift. I assumed it was a different version of the 4l60e transmission.

 

My 07 vortec Max isnt a 6 speed

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I'm gonna bump this up.... Since in NC these trucks are costing a premium, would getting an SCT tuner help out enough for me to get back into the 2008-2009 range??? I saw this at a dealership and it's an 09, and it says 6 speed..
http://www.31dodge.com/used/Chevrolet/2 ... a1e1c1.htm

 

The 6 speed also came in some 09s. Mine is a 2009 cc and has the 6 speed in it.

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Same here. Probably will never be able to go back to a 4-speed now. Love the Deep final drive ratio with my 3.42 rear end and 6sp. Could only imagine if I had the max trailering pack with the 6.2 and the 3.73s.... tire shredder :twisted:

OP, go with a 2010+ 5.3L but preferably the 6.2L (Can be hard to find) as they do not have Active Fuel Management (v4 fuel saving mode), and thus are impervious to all of the oil burning issues that the 5.3L has. There are good 5.3L's out there but its tough to tell when you're looking to buy one and you do not want to get stuck with an oil burner close to the end of the warranty. This can be prevented by buying a tuner or Range Active Fuel Management delete device before the oil burning issues start.

Just telling you what I wish someone told me. I got lucky as my truck doesn't use but hardly any oil but I'm about to roll over 100,000 miles and be out of my warranty, so if I did get an oil burner, I'd be up the creek unless I caught it early.

 

My 08 vmax had a 4 speed heavy duty auto trans in it. So not all vmaxes had the 6 speeds.

 

^^^ awesome thank you for that. I guess the 6 speed in an 09 is a little more rare...

 

^^^ yes it's kinda hard to find an 09 with a 5.3 and the 6 speed. I admit when I first got mine I hated the constant shifting of the 6 speed. I was used to my old 97 k1500. But now I love it and won't go back to a 4 speed.

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not sure if its area related but i had a 07.5 vortec max that was a six speed and my 09 right now is a six speed. both half tons. the dealer i went to to get both of them in my hometown in North Dakota had several 09's will the 5.3 and a 6sp trans.

 

It is just the commercial trucker in me, but the 6 speed is the cat's meow for me. I would even jump on an 8 speed if they made one. The manual mode is the only way I drive it. I like the control over the shift points, especially on the rolling two lane highways and back roads that the pickup spends more time on than anything else. I made it a point to check out the torque curve on the 5.3L engine and find the points where it levels off a little and adjust the shifting to match closer to the curve. From my experience, I have beaten the stock shifting in mpg by 1 mpg or more doing this, and it pulls soooo much better this way and by selecting the right gear for the terrain and RPM's, it does a lot less hunting for gears on the hills. The 6 speed was probably near the top of the reasons I even considered getting my 2013. Will never go back to an auto I have less control over.

 

I'm confused a little. Y'all talk about the M being a manual mode. On my 2012 silverado with the 6 speed I can change how many there are but I don't control when it shifts. For example I can put it into M5 and it will shift like any other automatic transmission but it won't go over the 5th. So like in M4 it won't go into 5th or 6th. Is this the same as y'all's or different.

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You have control if you work from the bottom up. For instance, I usually will start off with the button selector in M2 (M1 if I am pulling heavy or off road) and then make the shifts when I feel the RPM's are where I want them for the shift. Usually a little higher than GM has programmed them, except on WOT. If you start off in M5, sure, it will shift just like it does in D. You are fitting yourself in between a manual and an automatic. With manual mode and starting out at the lower gear setting, You are making the shifts, like a manual, but the auto is doing the actual shifting. So you have the best of both worlds.

Those of us that got exposed to the newer automated manual transmissions in heavy commercial trucks probably have a easier learning curve on how to do all of this. Those trucks give us a little more manual control than even the 6 speed in the Chevy does, but the principle and practice are pretty much the same.

 

Yea that makes sense, I usually keep it in M5 on the hw to keep it out of the v4 setting but I can see how you can do both. Thanks

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My 08 ltz 5.3 had the 4 spd, for me it was a much better and smoother running combination compared to the 6 spd that is in my 2011. Talk about a clunker, bout to throw an Allison in it haha.

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On the dash 4spd indicates PRND321 and 6spd indicates PRNDM. Diesels have PRNDM 1.

 

I ordered the "Range AFM" from AutoAnything (thanks Tom!!) on Tuesday, it arrived Wednesday with the forum discount. I installed it last night. Now that I have driven it ~50 miles I can tell you that it was worth every penny.. I can't figure why it's manufactured with the cheesy blue light so I put some black electrical tape over the light/lens. All is well now. The blue light looked a night lite shining on my feet. No more clunky driveline and transmission indecision while driving @slower speeds. GM ought to look at changing the software so that the cylinder deactivation cannot kick in unless you're over 50MPH..

 

My 09 2500 has the 6 speed and yes, for me, it is a huge improvement over the older 4 speeds.

 

Did these 6 speeds improve fuel mileage at all? What about reliability? Has anyone been having any issues at all with these newer transmissions?

 

I think it would a little but your gear ratio would also come into play when your talking mpg's. And whether it's a 2wd or 4 would also have to be considered...They're a great improvement over the 4sp's for towing..

 

I have a 5.3 and it has fuel management

 

You could always just listen to the motor for shifts to see what you have......