Why do you Cummins guys want more gears

4x4ord wrote:
I’ve heard a number of Cummins fans saying they are waiting for an 8 or 10 speed transmission before getting a new truck. Why? Does the Cummins struggle to get your trailer moving from a stop? Or are you running higher rpm cruising than you’d like? Or is it just because Ford and GM have 10 speeds?

Cummins owners typical want what both Ford and GM provide and it takes years. and sometimes decades, for the dodge engineers to read forums and figure out what they need to copy, and the easiest way to copy it.
LOL.

noteven wrote:
Because it is MOAR! speeds?

10 speeds and more are needed to optimize gas engines.

Why not use them in diesels too? Diesels don’t care.

While both types benefit...

Actually, the other way around, gas engines are happier over a wider range of RPM. If the engine is happy between say 1800-3500rpm, you can space the gears out more than if the engine is happy over 1500-2500rpm.

Of course really with modern engines, the power output is so great we are talking incremental improvements. Probably the biggest benefit is not having to mess around with a deep rear axle ratio for all but the heaviest trailers. It used to be a choice between good towing performance vs non-towing performance if you wanted to run in top gear. With 8-10 gears, the rear axle ratio is far less important and the truck will simply select the gear ratio it needs based on loading and speed.

rhagfo wrote:

4x4ord wrote:
I’ve heard a number of Cummins fans saying they are waiting for an 8 or 10 speed transmission before getting a new truck. Why? Does the Cummins struggle to get your trailer moving from a stop? Or are you running higher rpm cruising than you’d like? Or is it just because Ford and GM have 10 speeds?

Well our old 2001 Ram 2500 with Cummins 5.9 and 3.55 gears, worked to get going off the line, it didn't struggle, but it was working to get our 13,000# 5er moving, we likely had about 300 hp and 610 torque.

Now the same 5er behind the 2016 Ram CDT with Aisin and 3.73, 385 hp and 850 torque seems to not really working at all. Our towing (pulling) rating is 25,224#, so moving about half of what it is rated to pull.
The old Ram was pulling about 1,000# more than it was rated at stock.

The 2021 Cummins makes 1075 lbft of torque and Ram quit offering the 3.42 gears.

It just seems that all truck manufacturers are going to higher numbers of gears. I'm not sure its needed in a diesel though, but I'm not an engineer... heck I've never even been on a train before.

That said, I've never felt the need for more gears in my CTD. Plenty of grunt to get moving off the line and most of the time I'm towing its in 6th gear and rarely downshifts. Seems to me that Ram knows how the engine is supposed to work and designed a transmission that keeps the powerband where it needs to be.

4x4ord wrote:
I’ve heard a number of Cummins fans saying they are waiting for an 8 or 10 speed transmission before getting a new truck. Why? Does the Cummins struggle to get your trailer moving from a stop? Or are you running higher rpm cruising than you’d like? Or is it just because Ford and GM have 10 speeds?

Well our old 2001 Ram 2500 with Cummins 5.9 and 3.55 gears, worked to get going off the line, it didn't struggle, but it was working to get our 13,000# 5er moving, we likely had about 300 hp and 610 torque.

Now the same 5er behind the 2016 Ram CDT with Aisin and 3.73, 385 hp and 850 torque seems to not really working at all. Our towing (pulling) rating is 25,224#, so moving about half of what it is rated to pull.
The old Ram was pulling about 1,000# more than it was rated at stock.

Not needed. More speed towing is dangerous for many reasons, and you achieve a good speed now. Lugging any engine while pulling a weight not good either. Continual searching for correct gears can't be good. The best overall range for towing with that Cummins is around 1800 RPM so in my opinion not needed.

Because it is MOAR! speeds?

10 speeds and more are needed to optimize gas engines.

Why not use them in diesels too? Diesels don’t care.