6.6 Gas Tows 16K Review Video

brendon444 · October 21, 2019

Good review that came out a couple days from fast lane truck.

NWI Denali · October 21, 2019

Pretty disappointing showing. Seems the 6.6 gas is really crippled without the 10 speed and/or 4.10's.

brendon444 · October 21, 2019

2 hours ago, NWI Denali said:

Pretty disappointing showing. Seems the 6.6 gas is really crippled without the 10 speed and/or 4.10's.

Agree, it didn't downshift and was 25mph pulling the hill at points. I think 10 speed would of been a huge improvement.

ShotgunZ71 · October 21, 2019

The 10-speed would make NO difference at all if the shift parameters aren’t programmed accordingly. Use manual shift to lock out upper gears when towing in mountain or hilly areas and you don’t have this issue. It’s the way they program these trucks, shouldn’t be a surprise. Besides, that test is not a real-world example. No one would tow that much, up that grade on a regular basis, if ever. Certainly not using a naturally aspirated engine, either. I’ve learned to take anything on TFL Truck, especially with “Mr. Truck”, with a grain of salt.

bass mechanic · October 22, 2019

i saw this video, and the same trailer on the same hill with the duramax. no comparison. i live in Colorado and have driven this hill many times.

the speed limit is 60 mph and its 8 miles uphill. the duramax did it in exactly 8 minutes as full throttle application uop this hill with that load woulkd exceed the speed limit.

also the duramax did this with average of 4.5 mpg verses 2.5 mpg.

glad i got the duramax.

if you live on flat ground the gas will work just fine for you.,

TXGREEK · October 22, 2019

i saw this video, and the same trailer on the same hill with the duramax. no comparison. i live in Colorado and have driven this hill many times.
the speed limit is 60 mph and its 8 miles uphill. the duramax did it in exactly 8 minutes as full throttle application uop this hill with that load woulkd exceed the speed limit.
also the duramax did this with average of 4.5 mpg verses 2.5 mpg.
glad i got the duramax.
if you live on flat ground the gas will work just fine for you.,

Great video OP, thanks for posting! DMax all the way when towing heavy, especially with the availability of the engine break.

Sent from Above

SierraHD17 · October 22, 2019

Already said but even with 3.73 and the 6 speed the truck would have done fine if it could downshift correctly on it's own. Dropping to 2000 rpm wide open throttle is just asinine and shows whoever GM pays to tune needs a new career elsewhere. Anyone not doing a test of OEM's equipment capability would have manually downshifted the truck and kept the rpms in the powerband.

protovack · October 22, 2019

no one would actually tow that trailer up that hill with a gas 2500. Expecting it to somehow breeze up that mountain is fantasy thinking, and imagining the 10 speed would somehow solve the "problem" is also fantasy thinking. The TFL guys rag on the truck like it somehow should've done it faster, but again, fantasy thinking. This is a small block gas V8 pulling a 6600lb truck and a 16,000lb trailer, at high elevation. It's exactly the expected result, and it does not mean the 6 speed is not a good transmission, in any way. Sheesh. Apply some critical thinking! Everyone knows you don't pull extreme loads at high elevation in a naturally aspirated engine. It's essentially a clickbait video--"watch the poor naturally aspirated V8 suffer up the Ike gauntlet!" I mean, is anyone surprised?

kenny_r · October 22, 2019

Like I have said in prior threads....you have to admit that its impressive for a small block to drag that much weight up a hill and not overheat anything. I bet if you were to try that with an old 7.4 you’d be havin some issues somewhere.

HeySkippyDog · October 22, 2019

TFL proved to me they were nonsense when they loved the turbo 2.7 Silverado.

NO. WAY.

If you need to turbocharge your go-kart engine to tow under 7,000 pounds, in 2019, that's garbage for full size truck capabilities even at the half ton level.

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MTU Alum · October 22, 2019

The truck was very close to GCW and GVW. I would that combination at 23k before people.

#iworkforGM

CRApex · October 22, 2019

15 hours ago, protovack said:

no one would actually tow that trailer up that hill with a gas 2500. Expecting it to somehow breeze up that mountain is fantasy thinking, and imagining the 10 speed would somehow solve the "problem" is also fantasy thinking. The TFL guys rag on the truck like it somehow should've done it faster, but again, fantasy thinking. This is a small block gas V8 pulling a 6600lb truck and a 16,000lb trailer, at high elevation. It's exactly the expected result, and it does not mean the 6 speed is not a good transmission, in any way. Sheesh. Apply some critical thinking! Everyone knows you don't pull extreme loads at high elevation in a naturally aspirated engine. It's essentially a clickbait video--"watch the poor naturally aspirated V8 suffer up the Ike gauntlet!" I mean, is anyone surprised?

I am. I thought it would have done better and probably would have had the truck downshifted properly. The 2017 6.0 was tested by them with a 13500lb trailer and did it in 10:29. I was expecting the new 6.6 to be closer to that time, maybe not as quick due to the heavier trailer but closer.

kenny_r · October 22, 2019

Guess somebody needs to break the rules and tow 16k with their 6.0.lol

Or they need to take that new 6.6 and tow 13.5k with it.

i82much · October 22, 2019

I seem to recall the 5.3 doing pretty well with some extra gears. No, you cannot fix the fact that a naturally aspirated engine loses power at elevation, but having some more gears to keep that 6.6 at a higher RPM would have nevertheless made a big difference.

The 6 speeds are basically a TH350 or 400 with a steep first gear and a couple of overdrives. You add a gear between 1st and 2nd and between 2nd and third and you've really changed the game.