2015 Silverado & Sierra to get 8-speed transmission

[LongrangeLauber]

I believe the most common fuel efficient rpm is 2200-2400 so that makes sense

 

Sent while in 'Murica...

[KARNUT]

Back when I played with 454s mostly in impalas, with a 400 turbo trans and 373 gear I got 16 mpg on the freeway and 14mpg in town. I did use a 700r4 trans for awhile the trans back then couldn't handle the tq. The impala with the 400 would spin 3000 rpms at 60 mph. So to spin the kind of rpms you claim with 411 gears you must have been driving 45 mph or had some real over sized tires that will kill the gas mileage I love the 454s I dealt with back in the day, but to claim they could get the same gas mileage even at 2200rpm as todays chevy engines is a bit of a stretch. I even built a 76 nova with the impala set up still got mid teens on the gas mileage. The only 454 truck I had that I left stock had a 373 gear it got 13 mpg at 60 mph on the freeway. I would say that GM nailed it when it come to the engines of today even if I hate the V4. The last hwy trip I took I got almost 22 mpg at 72 mph, as much as I enjoyed the old big blocks I aint going back.

[Jsdirt]

I'd rather pay a little more in fuel than ALOT more in purchase price, taxes and insurance ... all to have it be worthless in one model year, & break down anyway. At least you can fix the older ones without a $2,000 Star Trek-looking device ....

[KARNUT]

I for one cant wait for the 8 speed. I have no problems with my 14 model, in two or three years when I trade the 8 speed will be the one reason I will do it. The 454 comparison with the 5.3 or 6.2 for fuel mileage was kind of foolish, I had a few of those great engines good on gas no way, better than the 460 or bid block mopars yes. They are the reasons I went to diesels before our government screwed that up.

[Jsdirt]

Yeah, don't even get me started on EPA diesels! What a GD mess ....

 

 

I have to admit - I love my 5.3, except for it's gutless low-end. I just dread the day all the electronic gizmos start failing ....

 

If GM gets this 8-speed right on the first try, I'll be shocked. Smart to wait a few years. If they start grenading, the internet will be abuzz ....

[MikeNH]

GM truck transmissions have been durable for years. Calibration can be questionable but they don't fail.

[DanMan_S]

GM truck transmissions have been durable for years. Calibration can be questionable but they don't fail.

 

Based on my current experience with my 6.2L and 6 speed, I can definitely agree with this. My transmission tune is so aggressive that the truck will easily spin the tires on upshifts with the 3.43 rear end. I've been driving it this way for nearly 60000 km so far and it hasn't missed a beat. I definitely don't baby this truck. I typically pull a nice burnout in the office parking lot whenever leaving work. I'm sure the bosses are impressed.

Edited August 26, 2014 by DanMan_S

[EX-F150 owner]

21-22mpg with my 10' 6.2 3.73 and it's stays in 6 th

I'd like to know how you are getting that?

[kovs]

Hand calculated and just drive 108km/hr hwy

That's with rolling on 305/45/22 tires. Just nice driving. If I get aggressive passing or leaving lights it drops quick lol

Only mod is cold air intake, throttle body spacer and magnaflow muffler.

Dad will get 22-23 on a hwy run with his 13'

Should have my lack bear tune in this week. Then I'm sure mileage won't be as good as I'll be into the pedal more often lol

 

 

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[Jsdirt]

Certainly won't get that here in MA with our diluted moonshine they call .. "gasoline" ..................

Edited September 2, 2014 by Jsdirt

[MikeNH]

Certainly won't get that here in MA with our diluted moonshine they call .. "gasoline" ..................

E10 is everywhere these days. It's the rolling hills and mountains in the northeast that do it. If I cruise steadily on the arrow straight and flat farm roads out here in MI at 55 for long periods I'll actually touch the 20-21 the window sticker claims. But on lower speed highways back in NH I would never come close.

 

That said, when I was at the dealership the factory rep claimed New England gas was crap and it made his cars run notably worse than stuff sold elsewhere.

[Jsdirt]

Yeah ... the pump SAYS E10 ... but have you ever looked at a Flex vehicle on a scan tool? Closer to 20% ....

 

Nobody seems to complain about that up here. Everyone is asleep!!

[Cowpie]

Probably the reason no one is pitching a fit, or even wasting time over how much ethanol is in the gas is because, like me , I have been using the stuff since the late 70's and never had any issues. Just not worth losing any sleep over.

[Jsdirt]

It's because people here don't know any better. If you enjoy losing 3mpg and therefore paying MORE at the pump in fuel taxes, well ... then I just can't understand what planet your conscience resides on.

 

People have NOT been using it since the 70's. Maybe in IA, but not in MA. Back then it was called GASOHOL ... and we had a CHOICE of whether or not to buy it. Most in MA didn't, because your HP/mileage degraded, and it caused all kinds of carburetor leaks, blown fuel lines, & rusty fuel tanks. Today in MA, there is NO CHOICE, and there is NO REGULATION OR TESTING of the actual percentage of ethanol added to each batch of gasoline. Sometimes you get 20% ... sometimes you get 12%. We're gettting ripped off!! Your buying diluted gasoline at full price, getting less MPG, less power, and less money in your wallet ... as usual.

 

Your from IA, so I gather this keeps you and/or your neighbor's employed - I get it ....... but ethanol DOES NOT belong in fuel, ESPECIALLY when we're NOT given a choice!!! This used to be the "Land of the Free" ... REMEMBER??

[MikeNH]

Massachusetts hasn't been land of the free for ages. That's why you people always to to NH on weekends/holidays.