4spd (4l60e) Vs 6spd (6l80e) Mileage Difference

Duramaximum · August 25, 2009

As of 2009, in the 1/2-tons, you can get the 6spd tranny in the crew cabs, but you can't get it in the ext. cabs. For those of you who have those trannies with the 5.3L engines, does it make that much of a mileage difference to have those two extra cogs?

I am looking at buying a new 2009 1/2-ton and want the 6spd, but can't justify the crew cab price. If the average fuel mileage numbers were substantially better, I might take a longer look at the crew cab.

What do you think?

Matt_ · August 26, 2009

well fuel mileage is very dependent on driving style....

with that said, the 6L80E is a .65 OD gear combined with a 3.42 rear with yields super low RPM's on the highway for great gas mileage while still yielding a gearing advantage off the line (unless you have 4.56s and stock tires with your 4L60E).

Im not sure what the difference in price is for the trucks you're looking at... but IMO it'd be worth giving up a few options to get the better drivetrain. Options can always be added on down the road whereas changing a trans & rear is an unlikely investment in the future...

Duramaximum · September 5, 2009

I test drove a 09 Crew Cab with the 5.3L and the 6spd. I'm convinced, I will wait until I can afford that tranny. It was just so smooth and put a lot of power to the ground. I pulled into traffic and got on the throttle like I would my 2000, and those tires broke loose and I swung that rear-end around so fast. The salesguy had a good laugh over that one. Then the other feature I really liked was the Manual mode where I could choose my own gears. Even that was a lot smoother and faster than I thought it would be. I had to double-check the rpms to make sure it acutally shifted.

I'm sold, 6spd all the way!

uh6tdrvr · September 5, 2009

Id definetly go with the 5.3. I dont know about an overall mileage difference but it does alot better job of keeping the engine in the power band plus the tow/haul mode works like tow haul should, down shifts to use engine braking. IMO it does nearly as well as a allison.....or close to it.

gabet95 · September 6, 2009

i got the 5.3 w/ 6spd tranny. I like it most of the time.

Sometimes after taking off, shifting between 2nd and 3rd gear is so hard it feel like you've got wiplash. It also sounds load like when your u-joints are worn. Truck only has 2,500 miles on it.

Everytime this happens my G/F looks over at me and says "See I told you to get the Tundra".

brims · September 7, 2009

i got the 5.3 w/ 6spd tranny. I like it most of the time.

Sometimes after taking off, shifting between 2nd and 3rd gear is so hard it feel like you've got wiplash. It also sounds load like when your u-joints are worn. Truck only has 2,500 miles on it.

Everytime this happens my G/F looks over at me and says "See I told you to get the Tundra".

Then you'd be walking.

rogersinsel · October 5, 2009

As of 2009, in the 1/2-tons, you can get the 6spd tranny in the crew cabs, but you can't get it in the ext. cabs. For those of you who have those trannies with the 5.3L engines, does it make that much of a mileage difference to have those two extra cogs?

I am looking at buying a new 2009 1/2-ton and want the 6spd, but can't justify the crew cab price. If the average fuel mileage numbers were substantially better, I might take a longer look at the crew cab.

What do you think?

My 09 Tahoe gets 17-18 city and 19-22 highway, if I keep it slow. 60 or so. If I 70-80 the best I can get is 19 or so. The 6 out drives the 4 speed. Get the 6!

jf781 · October 5, 2009

My 09 Tahoe gets 17-18 city and 19-22 highway, if I keep it slow. 60 or so. If I 70-80 the best I can get is 19 or so. The 6 out drives the 4 speed. Get the 6!

Have to agree I got on the mid to high side of 19 avg over 700 miles running 75-80 the whole way.

Toadz · November 21, 2009

i got the 5.3 w/ 6spd tranny. I like it most of the time.

Sometimes after taking off, shifting between 2nd and 3rd gear is so hard it feel like you've got wiplash. It also sounds load like when your u-joints are worn. Truck only has 2,500 miles on it.

Everytime this happens my G/F looks over at me and says "See I told you to get the Tundra".

You need a new girlfriend. My /fiance would slap ME if I talked about getting a Toyota, even she knows better.

Get the 6-speed. 4-speeds should have been done away with in the 70's.

mattgob86 · December 3, 2009

Well the 6 speed is sold to me!

You guys that love it with the 5.3, the 6.2 is a BEAST with the 6spd

So you get the big "APPROVED" from me

rodram · December 3, 2009

... with respect to the choice of 4-sp and 6-sp on the 5.3L 1500's ... there is more to consider than some little bit of potential gas mileage saving

... the 6-sp is just going to run smoother, and will be less prone to overheating, and less prone failure at 100,000 miles (like many 4L60E's do) ... the 6-sp a stronger and more reliable transmission.... period!

... can you really justify getting a weaker/flawed transmission when you know there is a better choice

... for the guy with 2500 miles on his and having rough 2-3 shift... take it to the dealer to see why that shift solenoid is building up so much pressure before it shifts... something (seal on the solenoid..???) might be leaking and can be fixed easily on warranty before it causes other internal damage

... as a side note ... in my opinion ... I do not know why GM keeps putting 4L60E's in trucks... these are known to be a light duty transmission (hey, I've got one and I now know it's limitations....) and again in my opinion these just do not or cannot live up to the expectation of a fullsize truck owner ... if for whatever reason a 4-sp needs to be in a base model, then at least use one of the upgraded 4-sp trans (the 65 or the 70) or use the 4L80E 4-sp which has proven to be a truly much tougher transmission.

... if getting a new 1500 truck, I would prefer the ext cab... but if that meant I was stuck with the 4L60E, then Bye Bye extended cab; Hello Crew Cab.... ( I could learn to live with the slightly smaller box)

kawtoy_77 · December 3, 2009

I wish I had the 6spd

Badass69 · December 4, 2009

... with respect to the choice of 4-sp and 6-sp on the 5.3L 1500's ... there is more to consider than some little bit of potential gas mileage saving

... the 6-sp is just going to run smoother, and will be less prone to overheating, and less prone failure at 100,000 miles (like many 4L60E's do) ... the 6-sp a stronger and more reliable transmission.... period!

... can you really justify getting a weaker/flawed transmission when you know there is a better choice

... for the guy with 2500 miles on his and having rough 2-3 shift... take it to the dealer to see why that shift solenoid is building up so much pressure before it shifts... something (seal on the solenoid..???) might be leaking and can be fixed easily on warranty before it causes other internal damage

... as a side note ... in my opinion ... I do not know why GM keeps putting 4L60E's in trucks... these are known to be a light duty transmission (hey, I've got one and I now know it's limitations....) and again in my opinion these just do not or cannot live up to the expectation of a fullsize truck owner ... if for whatever reason a 4-sp needs to be in a base model, then at least use one of the upgraded 4-sp trans (the 65 or the 70) or use the 4L80E 4-sp which has proven to be a truly much tougher transmission.

... if getting a new 1500 truck, I would prefer the ext cab... but if that meant I was stuck with the 4L60E, then Bye Bye extended cab; Hello Crew Cab.... ( I could learn to live with the slightly smaller box)

With regards to the 2nd to 3rd gear slip or rough shift, it's not all that uncommon. My 09's 6L90E does it and the dealers have no solution for it. It all but disappears when warm but does it only when the fluid is cold. According to the dealers the scan tool shows nothing out of the ordinary, even when they reproduced it.... and of course it throws no codes. At first they tried blaming it on my 265/75/16 tires and then the weight the truck carries along with its roof rack.......... Umm it's a 3/4 ton with about 1500 lbs added to it..... if the tranny can't handle that maybe it shouldn't be in the truck. Then I noticed a few 6 speed guys complaining about it on here with stock trucks and no solutions. The tires make absolutely zero difference in the shifting, does it with 245's on it as well. Not to mention I can name about a dozen 6L90E trucks with no tuning changes and 265's where 245's were with no shifting issues. I just won the lemon lottery. Local dealer told me to drive it until it grenades and not to worry about it as they would warranty it up to 160000 km anyways. It's a fleet truck and I won't have it that long anyhow.

That being said I am crossing my fingers that my 2010 I have ordered of my own doesn't do it. I am tuning it right away to fix up the sloppy shifts they all have. That be said I like this tranny when coupled with 373 gears. Nice mix of driving and pulls very hard...... especially with the 6.2 in front of it.

HawkScot · December 4, 2009

I seem to recall a TSB on the 2-3 shift when cold (at least for the 08 Yukon XL Denali 6 speed). They replace some o-rings in the middle of the trans. They have to remove the trans and tear it down to do it.

kawtoy_77 · December 4, 2009

I have that same problem, but its intermittent.... doesn't matter if its hot or cold, it does it whenever it wants, and it goes away whenever it wants..... same as it came. Still shifts fine. Fluid still tests fine, and its clean.