Anyone know why trucks sold with manual transmissions are somewhat lower horsepower? And also, the chassis cab, at least with Dodge trucks, is slightly "derated".

 

no the manual tranny trucks make more power

 

Well then I'm reading the Dodge truck website incorrectly, and I've seen the same thing posted at other manufacturers sites as well.

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Here's a copy and paste from the Dodge website:

The 6.7 Cummins turbodiesel will be essentially unchanged, but with a new particulate feature that slashes nitrides of oxygen by 90%; in the pickups, the engine produces 350 hp at 3,000 rpm, and 650 lb-ft of torque at a stunning 1,500 rpm, just off idle (automatic transmission). With the G56 manual transmission, the Cummins puts out 350 hp and 610 lb-ft of torque; with the chassis cabs, 305 hp and 610 lb-ft of torque.

 

for instance my auto has a 180hp pump the manual has a 215hp pump

 

Just a guess, but I think they do it because they are getting into the power range where you could easily hurt something if you don't shift it right. With the auto, the computer is in control. I would imagine it is to reduce warranty claims in the long run.

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He's talking new trucks, which he is correct the manual is derated.

 

I don't know about pumps. I just know what I see. And on their website, it's clear. The manual tranny trucks don't make as much torque, and the chassis cabs make less torque and less horsepower. These are new models of course. I'm pretty sure the same thing applied to my Fords. My F550 was a manual tranny, and my F350's were automatic, and they made more power.

I think Matt from Wyoming may have a point, BTW.

 

my auto 99 is rated at 215 and the manuals are 235 i think it usually goes the other way ( manual is a higher rating) in my opinion

 

ok i stand corrected my bad

 

The 6.7 with the G56r manual transmisson is rated at 610ft-lbs because the clutch could not handle the 650ft-lbs of torque so they electronically turned it down.

 

Now we're getting some answers. I wonder why the truck makers would not put in a clutch that could handle the higher torque? I don't doubt that might be the reason for derating the engines, but how ridiculous it seems to me. It used to be that anyone that raced (drags) and had real power always opted for the manual tranny. Now it's the other way around. In fact, the Porsche turbo is faster from 0 to 100 with the automatic tranny, I guess because it holds the power and shifts faster than the manual with the man behind the wheel doing the shifting.