8 Speed Auto for HD trucks

The end ratio of high gear is going to be in the neighborhood of 0.68/1 no matter if it's a 6 speed or a 20 speed. Assuming we're talking HD gassers, which hit their powerband at a high rpm, other than squeezing an almost impossible to notice MPG gain the extra gears don't give you all that much.

Now in a truck that's used by Joe Schmow to haul a couple of bags of mulch between work commutes, or Soccer Sally to haul home the groceries, which are what the vast majority of light duty trucks are used for it makes all the sense in the world to have some extra ranges between top and bottom. In a HD truck being used as an HD truck it does not make as much sense. I suspect I am getting an 8 or 10 speed through no choice of my own the next time I buy a truck, but my current 2015 GMC 2500 with its 6 speed has more than enough intermediate gears, I don't know what I would be gaining with 2 or 4 more other than more heat from more shifts and additional parts to wear or fail internally. I was not looking for mileage when I bought it.

This forum often times seems like a bunch of old codgers who don’t like change.

I spend a lot of time in rental vehicles. I really like the 10 speed in the F150 (driving one right now) and the Expedition. The 8 speed in the RAM is almost as nice. Both are better than a 4/5/6 of a few years ago. I’m sure this 8 speed in an HD would be better than what is currently available.

I’m not convinced that a CVT is the right option for a truck, but in the right car, they are ok. Nissan seems to have it worked out in their Altima as far as driver experience. And my Lexus RX has one that I am happy with.

Ram would likely have an advantage with CVT transmissions in high hp and torque applications. The CASE-IH tractors have been available with CVT transmissions for years. While it is not a direct application, I am sure they have learned a lot in making CVT work in tough conditions.

Me Again wrote:
Maybe Diesel/Electric will take over like Locomotives and Ships!

Basically that is the Volt, except it isn't diesel and it has a battery pack to store energy.

Maybe Diesel/Electric will take over like Locomotives and Ships!

valhalla 360 wrote:
And the old guys probably said the same thing when automatics went from 2 to 3 gears.

Ya, I have a 66 Chrysler 300 convertible with a 440 TNT and Torqueflite transmission. Great tranny in its day, three speeds compared to GM's Powerglide two speed, but terrible compared to today's transmissions

CVT's have come a long way. Nissan's use a steel belt or chain and a planetary gear.

...Nissan's many programming changes to the CVT are so substantial and so mimic a regular gearbox that if you did not know a CVT from a sock drawer, you would never question how the power from the engine is transferred..”- Autotrader

Me Again wrote:
OK, so in 1976 to 1979 I drove a truck with a 13 speed Roadranger tranny. Along came people have did not know how to drive a manual tranny, so Firetrucks and garbage trucks got automatics. The CVT trannies will complete the circle. BTW, I really liked the 13 speed, let the clutch out in the tank yard in Port Angeles and put it back in at Forks 70 miles away! With lots of shift in between.

Chris

I think you may be interchanging "not know how" and "have no desire to". I for one would not want a job driving a garbage truck while having to push a heavy clutch in hundreds of times a day. It's probably important not to stall a firetruck engine when it's running pumps and other equipment, no matter how unlikely that is with an experienced driver.

My first tractor-trailer experience was on a 13-speed too. ;)

valhalla360 wrote:

Me Again wrote:


I towed with a 2001.5 gear bound 47RE for years. The 6 speed Aisin resolved that. I see not need for more gears.

I have golf carts and had snowmobiles with CVT setups. The higher powered snowmobiles required routine maintenance. The golf cart's not so much.

And the old guys probably said the same thing when automatics went from 2 to 3 gears.

CVT's used in trucks will be nothing like the snowmobile transmissions. Of course they aren't going to use a simple rubber belt for a truck towing 15k lbs. That's also why they haven't put the trucks out with CVT's yet but I can guarantee someone is working on it.

PS: Just looked up and there is a consortium of semi tractor manufacturers working on one.

OK, so in 1976 to 1979 I drove a truck with a 13 speed Roadranger tranny. Along came people have did not know how to drive a manual tranny, so Firetrucks and garbage trucks got automatics. The CVT trannies will complete the circle. BTW, I really liked the 13 speed, let the clutch out in the tank yard in Port Angeles and put it back in at Forks 70 miles away! With lots of shift in between.

Chris

Me Again wrote:


I towed with a 2001.5 gear bound 47RE for years. The 6 speed Aisin resolved that. I see not need for more gears.

I have golf carts and had snowmobiles with CVT setups. The higher powered snowmobiles required routine maintenance. The golf cart's not so much.

And the old guys probably said the same thing when automatics went from 2 to 3 gears.

CVT's used in trucks will be nothing like the snowmobile transmissions. Of course they aren't going to use a simple rubber belt for a truck towing 15k lbs. That's also why they haven't put the trucks out with CVT's yet but I can guarantee someone is working on it.

PS: Just looked up and there is a consortium of semi tractor manufacturers working on one.