Performance of 5.3L 8-speed vs 5.3L 6-speed

[Liopleurodon]

Hey everyone I am a long time lurker, first time poster looking for some buying advice for my next GM truck. I currently own a 2015 Silverado CCSB LTZ 4x4 with a 5.3L/6speed/3.42 power train. I am looking to upgrade to a 2017 LTZ but I have a few reservations regarding the performance of the 8 speed transmission.

 

Some background, this truck is the first vehicle I have ever owned that feels legitimately quick. I like the feeling of power and how quick it moves hammer down. I don't want to lose that. After reading some reviews I am not really sure what to expect going from a 6 speed to 8 speed.

 

Here's a review of a 2016 Sierra All Terrain X 4x4 CCSV with a 5.3L and 8speed

http://www.caranddriver.com/reviews/2016-gmc-sierra-1500-4x4-all-terrain-review

Its performance is as follows (its very similar to my 2015 6speed)

 

Zero to 60 mph: 6.6 sec

Rolling start, 5-60 mph: 7.1 sec

Top gear, 30-50 mph: 3.4 sec

Top gear, 50-70 mph: 4.4 sec

Standing ¼-mile: 15.1 sec @ 92 mph

 

 

Here's a review from the same source for a 2016 Silverado LTZ CCSB 4x4 with a 5.3L and 8 speed

http://www.caranddriver.com/reviews/2016-chevrolet-silverado-1500-z71-53l-8-speed-automatic-test-review

 

 

Zero to 60 mph: 7.2 sec

Rolling start, 5-60 mph: 7.7 sec

Top gear, 30-50 mph: 3.9 sec

Top gear, 50-70 mph: 4.9 sec

Standing ¼-mile: 15.4 sec @ 90 mph

 

 

Any idea why the Chevy is so much slower? The only powertrain difference I could find was the performance exhaust on the GMC. What kind of performance can I expect if I order a 17 LTZ 5.3L CCSB 4x4? Thanks in advance for your answers!

[combat1500]

Drive both see what your happy with.

 

SLT's all come in 8 speed

Edited July 11, 2017 by combat1500

[UplandPa]

Those 1/4 mile times are impressive , I think you"ll be very happy. Even trucks with the same drive train will run different times, especially if run on different days! I think most people are happy with the 8sp.

[SouthernSilveradoGuy85]

Personally I think a 6 speed is all you need. The 8 speed just gives better fuel mileage, but from what I've seen it's not really enough of a difference if you just daily drive it. Now I know having an 8 speed over a 6 speed is better if you do a lot of towing especially in hilly areas or mountains. I guess sooner or later a pickup truck will have as many gears as an 18 speed semi truck or dump truck. Even most semi trucks (ordinary once, not ones built for heavy loads) only have a 10 speed. So like I said, an 8 speed is better if all you use the pickup for is towing, especially in hilly areas and mountains. But, for daily driving I don't think it's a big enough advantage to trade in a newly bought truck for another brand new one just to get the extra 2 speeds. At the end of the day, it's also just more that can go wrong. You have 8 gears/clutch packs that can fail over just 6. Same as if you buy a truck with all these extra features, just more that can and will go wrong that you'll have to fix. Of course that doesn't matter if all you do is lease or once you pay off a vehicle you trade it in for something else so you get rid of it before major things go wrong. Just my opinion though so get what you want. I just think the amount of gears are getting a little out of hand in a passenger vehicle.

[Liopleurodon]

Thanks for all the responses. I'm not looking to upgrade just to get the 8sp, The lease on my 15 is almost up. I guess i am trying to decide if I really want to lease a 2017 with the 8sp or if I would rather just buy the truck I have now. As far as I can tell it is impossible to get an LTZ (or SLT) without the 8 speed.

[Mark Diedrich]

Hey everyone I am a long time lurker, first time poster looking for some buying advice for my next GM truck. I currently own a 2015 Silverado CCSB LTZ 4x4 with a 5.3L/6speed/3.42 power train. I am looking to upgrade to a 2017 LTZ but I have a few reservations regarding the performance of the 8 speed transmission.

 

Some background, this truck is the first vehicle I have ever owned that feels legitimately quick. I like the feeling of power and how quick it moves hammer down. I don't want to lose that. After reading some reviews I am not really sure what to expect going from a 6 speed to 8 speed.

 

Here's a review of a 2016 Sierra All Terrain X 4x4 CCSV with a 5.3L and 8speed

http://www.caranddriver.com/reviews/2016-gmc-sierra-1500-4x4-all-terrain-review

Its performance is as follows (its very similar to my 2015 6speed)

 

Zero to 60 mph: 6.6 sec

Rolling start, 5-60 mph: 7.1 sec

Top gear, 30-50 mph: 3.4 sec

Top gear, 50-70 mph: 4.4 sec

Standing ¼-mile: 15.1 sec @ 92 mph

 

 

Here's a review from the same source for a 2016 Silverado LTZ CCSB 4x4 with a 5.3L and 8 speed

http://www.caranddriver.com/reviews/2016-chevrolet-silverado-1500-z71-53l-8-speed-automatic-test-review

 

 

Zero to 60 mph: 7.2 sec

Rolling start, 5-60 mph: 7.7 sec

Top gear, 30-50 mph: 3.9 sec

Top gear, 50-70 mph: 4.9 sec

Standing ¼-mile: 15.4 sec @ 90 mph

 

 

Any idea why the Chevy is so much slower? The only powertrain difference I could find was the performance exhaust on the GMC. What kind of performance can I expect if I order a 17 LTZ 5.3L CCSB 4x4? Thanks in advance for your answers!

[Mark Diedrich]

Just curious, was the rear ends the same in the 2 trucks? I could see a difference like that if one was a 3.08 vs 3.42

Or possibly one at higher elevation and the other at sea level?

Plus I'm sure that not all trucks are the same...

[Boardmember]

There are '16s and '17s with the 5.3 and 6 speed, SLT and otherwise. I've wondered why GM offered the '17 SLT 5.3 3.42 with the 6 speed.

 

Although I have my theory.

 

I've had both in a 2016 SLT. My Iridium 4wd was the 8 speed. Mechanically it might have been ok but the software was crap. It was awful in short. I now have a 2wd with 6 speed and it's MUCH more civilized. It drives like just about every other vehicle I've owned. And my mpg is good, but it has been with both trucks.

 

A friend just bought a '17 Silverado LT with the 6 speed and I was really happy for him.

 

Isn't the 6 speed rated to get a little better mpg also?

Edited July 11, 2017 by Boardmember

[Boardmember]

Duplicate

Edited July 11, 2017 by Boardmember

[Truck916]

My 8 speed shifts great. Definitely the better route.

[Bikemobile]

My 8 speed shifts great. Definitely the better route.

I have driven both. A 2014 Sierra AT 5.3/6 and my 2017 5.3/8.

The 14 drives nice no complaints but the 17 feels quicker. It takes about 3k miles for the 8 speed to learn how not to be a spaz idiot. After that its good.

[mookdoc6]

Firstly, Your not going to get as good of Fuel Economy with the 8speed. It is also a few tenths slower at all comparison times/tested across the board mainly due to the extra gear shifts and the final being different from Six and loosing the MPG's

 

I own an 8l90 with 5.3 because the first 6peed on GM trucks angered me to the point of medication? This transmission takes FOREVER to LEARN........Like 10-20K NO BS! IT also is demanding of constant Torque and massive amounts of it or it acts silly. If you tow on grades or drive up and down hills all day this thing is a beast! I like the fact that I can go up and down grades with the cruise control on and pitter/patter at 1500-1600RPM's and it does not drop down a gear just keeps on going up the grade! Talk to me FERD about that going up hills?

 

Anyway, If I had to do it all over again....It would be 6.2L and 8speed! Absolutely, the heaven is there son. So what you loose an MPG literally that is all...........

Edited July 11, 2017 by mookdoc6

[combat1500]

Firstly, Your not going to get as good of Fuel Economy with the 8speed. It is also a few tenths slower at all comparison times/tested across the board mainly due to the extra gear shifts and the final being different from Six and loosing the MPG's

 

I own an 8l90 with 5.3 because the first 6peed on GM trucks angered me to the point of medication? This transmission takes FOREVER to LEARN........Like 10-20K NO BS! IT also is demanding of constant Torque and massive amounts of it or it acts silly. If you tow on grades or drive up and down hills all day this thing is a beast! I like the fact that I can go up and down grades with the cruise control on and pitter/patter at 1500-1600RPM's and it does not drop down a gear just keeps on going up the grade! Talk to me FERD about that going up hills?

 

 

 

Anyway, If I had to do it all over again....It would be 6.2L and 8speed! Absolutely, the heaven is there son. So what you loose an MPG literally that is all...........

 

 

You can put the 8 speed in L5 (M5) and it will only shift 1st 5 speeds and it seems to do it alot smoother and faster then just leaving it in D.

[Sierra706]

The 8 speed is slower to 60 versus the 6 speed because of an extra shift. It's final drive ratio in 8th gear is slightly better, and it has the advantage of staying at low rpms more often for fuel savings. That's coming from car and driver.

 

 

Sent from my iPhone using Tapatalk

[Roddy8]

On 12/07/2017 at 7:01 AM, Bushleaguechew said:

The 8 speed is slower to 60 versus the 6 speed because of an extra shift. It's final drive ratio in 8th gear is slightly better, and it has the advantage of staying at low rpms more often for fuel savings. That's coming from car and driver.

 

 

Sent from my iPhone using Tapatalk

6 speed is quicker by a fair bit 0-60