You will get the 6 speed with all 5.3's in 2010 unless you select higher (numerically) than 3.42 gears, that puts you back into the 4 speed for some reason (for one 4.10 rear gears would be ridiculous with a 4.03 first gear in the 6 speed, equiv to like 5.13 rear with a 4 speed's first gear!!). Not sure why anyone would want that.

I went to the US GMC site to build your own and it defaults to 2009 on first page before you even select sierra, you have to select 2010 before you build...so not sure what happened there, you might have been in 2009 because I only saw 3.73's as highest (numerically) ratio....rcsb with 5.3 and 3.42 gear (max) will get 6 speed.

Pic attached, note picture shows crewcab but summary is for reg cab, which is what I built.

 

I want one...

 

How? The 4L60E came w/. a 3.06 1st gear. Unless u mean thru TQ multiplication. Cause the 1st gear on 6spd is 4.03. If by that, yes they're similiar. The 6A will net better MPG as u said, & less drop between gears =

 

And the 6l80 would hold up to a 6.0L/6.2L swap better than the 4l60/70's!!! That would be an easy bolt in swap and not have to worry about the trans.

 

You beat me to it. I was just typin to add, the 6L80E should be stronger. Let's hope the performance tranny builders & parts makers, embrace it, & offer goodies to upgrade the weak pts.

 

Anyone have any idea what the difference in gas mileage the 6 speed would give you with the 5.3? Its not listed anywhere on their site.


Edit: doing some google searches... I came up with 15 city and 21 highway.

 

WE NEED ONE MORE THING GM


the 6.2 in a 1500 reg cab trucks

 

I don't know about better mileage with the 6L80 on the 5.3. How much power does it take to turn that box over. Granted it's mandatory behind the L92.........

 

My girlfriend just got one @ the beginning of last week. It's a GMC Sierra SLE 4x4, and damn is it a nice little regular cab. The thing handles like it's on rails (well for a truck anyway), and even though I haven't "gotten on it" (waiting for break in period to pass) it's damn quick! I'll report back in the next week or so after we do the first oil change and get a chance to go full throttle. She just passed 1400 miles, so it's coming quickly. BTW, this is a work truck, hence the high miles already traveled in two weeks.

 

what would be needed to make a six speed work with are trucks now that the 2010 are coming out with them. maybe cpu and reprogram.