I drove the new 8-speed yesterday

[pro-v eddie]

I too am experiencing sloppy inconsistent shifting in my 6L80. The Denali is going in on 9/2 to be looked at. What can I expect? Program changes of shift points or excuses? This transmission has had the same problems since 2006 and yet they still install them in todays cars without corrections. Let's see how far I can use the 2 year/24000 mile warranty. Also, would they be able to swap out the 6L80 and install the 8L90? Just a thought?

[Z45]

The 6L80E and 6L90E were considered filled for service life transmissions. They were not supposed to be opened any sooner than 100k miles as they are factory filled in a clean room so no contaminants gets into them.

 

I am looking forward to see the new trucks and hope the review is right in shift feel as if what was said is right it will suck to not be able to tune out the crappy factory calibrations.

Then why do the owners manuals recommend changing the fluid as soon as 45,000 under severe driving.

 

Note - Filled for life means really nothing, it the trans failed at 20,000, that was its life. Its the life of the component, not the life of the vehicle.

[HondaHawkGT]

Why not offer 3.42, 3.73 gears and ditch the pushrods and do a DOHC 5.3L engine with Direct injection and cylinder deactivation.

 

 

 

DOHC presents more drawbacks than advantages in a naturally aspirated application. GM's OHV V8's make tons of power with a flat torque curve. C6 and C7 Corvettes have been outperforming DOHC exotics costing 2-3 times as much with nothing more than 2V pushrod engines. The sluggish characteristics of GM's trucks is due in large part to the way the 6L80 is programmed to meet CAFE regulations.

[66nova]

Also, would they be able to swap out the 6L80 and install the 8L90? Just a thought?

 

Very doubtful. While I'm sure it can be done, i don't expect it to be plug and play. Most likely much like a 6speed swap in a GMT900 truck. It can be done, but requires a lot (a lot) of work including swapping the entire engine/trans wiring harness.

[MikeNH]

 

DOHC presents more drawbacks than advantages in a naturally aspirated application. GM's OHV V8's make tons of power with a flat torque curve. C6 and C7 Corvettes have been outperforming DOHC exotics costing 2-3 times as much with nothing more than 2V pushrod engines. The sluggish characteristics of GM's trucks is due in large part to the way the 6L80 is programmed to meet CAFE regulations.

x2

 

GM V8s are the best on the market- they make good power and get good fuel efficiency in a smaller, lighter package. They're also way easier to mod for power than something like Ford's 5.0.

[thetruck454]

x2

 

GM V8s are the best on the market- they make good power and get good fuel efficiency in a smaller, lighter package. They're also way easier to mod for power than something like Ford's 5.0.

 

x3

 

Powertrain is the last area GM needs to improve in their trucks/sports cars