2015 Silverado & Sierra to get 8-speed transmission

[InertiaFaze]

As announced, look for a mid-2015 introduction of the 8 Spd and it will be paired with 6.2L engine only. This was not a joint venture with any other manufacturer.

[MikeNH]

I heard a rumor last fall that it was coming out, also heard that GM worked with Dodge on this along with the turbo diesel V6 that Dodge currently offers.

No. GM worked with Ford on the six and upcoming 9/10 speeds. GM developed the diesel that Ram has but due to mergers and sell offs Fiat got the rights to it and is using it here in the trucks and SUVs.

 

Still don't get why people feel cheated. Who really brags about how many gears you have? 6 works perfect, once tuned.

[sirbOOm]

How does one "tune" the clunky 6-speed? So damn sick of it...

[Daryl Z71]

How does one "tune" the clunky 6-speed? So damn sick of it...

 

 

Black Bear Performance

[InertiaFaze]

No. GM worked with Ford on the six and upcoming 9/10 speeds. GM developed the diesel that Ram has but due to mergers and sell offs Fiat got the rights to it and is using it here in the trucks and SUVs.

 

Still don't get why people feel cheated. Who really brags about how many gears you have? 6 works perfect, once tuned.

The RWD 6 Spd in LD and HD trucks (not the Allison in the Diesels) was developed exclusively by GM and is not used by any other manufacturers.

[j-ten-ner]

Most of the half ton trucks are used as grocery getters or parked in front of the night club.

That's where Ford sees the chance to sell the F150 with a moped engine.

 

The majority of us still want V8 engines. But there is only so much one can do to keep the fuel economy in check w/o compromising the performance.

AFM, direct injection, electronic ignition system you name it.

So it is necessary to look elsewhere along the drive line. The converter clutch already exists. Next in line are the gears.

 

On top it'll help to have a good fuel economy but also better towing capacity because the engine is running more and more close to the best performance parameters.

 

And on the second thought...it might be not a bad idea not to waste time to "fix" the six-speed.

But only if they do it right this time with the eight-speed.

 

so long

j-ten-ner

[MikeNH]

The RWD 6 Spd in LD and HD trucks (not the Allison in the Diesels) was developed exclusively by GM and is not used by any other manufacturers.

My bad. Upon further investigation GM and Ford did transaxle 6-speeds together. I'm gonna blame this on lingering jetlag.

[STINSAN3]

Should be pretty good.

[GPGuy]

Should be interesting to see the mpg numbers between the 6.2 8 spd and 5.3 6 spd.

[Big Whiskey]

3.08 and the 8 speed is going to be the new standard

 

I sure hope not.

 

3.08 with a 8 speed...... 3.08 no thanks, 8 speed maybe....

 

Exactly. 3.08's are terrible, regardless of the transmission.

 

I'm with you on that! I bet in 8 gear it will barely pull itself over an overpass with that gearing.

 

Thank you. Someone else who gets it. An 8-speed is great, but the final drive ratio is what really matters as far as drive-ability goes. I have no interest in driving a truck that down-shifts from 8th to 7th every time I sneeze or cough, haha

[j-ten-ner]

I don't think that the final ratio will be sooo much different form what it is now.

 

To add more gears is to fill the gaps between the gears. To keep the engine at a (close to) constant rpm.

Especially under load is the most fuel efficient rpm around the max torque curve.

 

so long

j-ten-ner

[CRSilverado]

I don't think that the final ratio will be sooo much different form what it is now.

 

To add more gears is to fill the gaps between the gears. To keep the engine at a (close to) constant rpm.

Especially under load is the most fuel efficient rpm around the max torque curve.

 

so long

j-ten-ner

8th will be taller than our 6 speed at .65. 6 speed is .67.

 

1st 4.552

2nd 2.959

3rd 2.074

4th 1.691

5th 1.268

6th 1.000

7th 0.847

8th 0.650

[Guest Damon T]

Well crap. Now do I wait to get this one or get the 2014 5.3? I'm guessing the mpg will be similar with more power in the 6.2

[Cowpie]

12k tow rating with a 3.08 gear? I cant believe they would do it.seems it would burn up the rearend dam quick

 

Really? Kinda wonder why I haven't burned up the 2.64 rears in my semi truck behind an 18 speed with a 550 hp 1850 lb torque engine yanking around 80,000 lb. And the truck just turned over 294,000 miles and runs great. The diff ratio is not the issue if you have the right gears and spreads between them in the transmission. I would be more at issue with the 3.08 in a pickup only because most of my driving, both pulling and not, is below 65 mph. Most of time I don't even use the 6th gear in my 2013 using 3.42 diff ratio. I haven't let it go to 6th is weeks. Just can't imagine the 8 speed with 3.08. I am wanting to put 4.11 in my diffs so that I can at least use all 6 gears comfortably for the hilly roads i frequent. Again, even at 65 with 4.11 and stock rubber, I wouldn't be turning more than 2100 RPM, which is right at the first plateau on the torque curve on my 5.3L. Get best balance of economy and power and reduced shifting cruising at 1900-2100 RPM.

Edited August 17, 2014 by Cowpie

[gonzoid]

ring gear in a pick up much smaller and lighter than a semi.Thus the difference

 

My money is on a 3.42 ratio for the 6.2 truck not 3.08