GM to Offer 8-speed Transmission

[Traveler II]

General Motors will offer a new eight-speed automatic transmission in the next generation of full-sized pickups and SUVs it plans to launch in early 2013.

[campswithcritters]

I hope it is not like the 10 spd I have in the FL, takes 5 shifts to cross a four lane road at an intersection!

[Chief409]

Why so many gears. Are the pick up's going to have a CVWR of 80,000 #, or are the new engines that weak.

Jeff

[Roger]

I'm sure it is for fuel economy. If you can narrow the range of engine speeds needed you can improve efficiency in that range.

[Chief409]

The 2011 and newer Ford 6.7's have a 6 speed (2 overdrive) auto tranny, a engine with 400 HP and 800 foot pounds of torque with the torque range starting at 2000 rpm. At 60 mph my truck is running 1650 rpm with 3:73 rear gears in 6th. Going over a 4000' pass with 6% uphill grades pulling the 'Bird, the truck shifted to 5th on the steepest portions, while holding 63 mph, and 4th when I wanted to accelerate. Uphill.

But compare the 6 speed tranny size to a 4 or 5 speed, the 6 speed is much larger. And more complex. What is the advantage of 2 more gears for a light truck like a pickup?

Jeff

[Mike Clay]

Just like Roger said it will hold your rpms and boost better without the jump in gears. At this point its all rumor anyway so really not going to worry about it right now.

[EAW]

When I googled "new gm 8 speed transmission" the results showed up like gm is behind Ford and Ram on doing it. A little closer gear ratio change in the upper gears would be nice if it don't constantly hunt for a gear. The articles imply that Ford and GM are going to build their own with GM doing it in the USA, hopefully Ford will do the same and put our people to work. Chrysler should have the gear hunting bugs worked out of the electronics first since they are starting with the cars.