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I was down at the dealer today and thought I would take a look at the 3/4 Ton Cummins trucks. I noticed that some have the 5 speed with the standard Cummins and some have the 6 speed with the H.O. Cummins. I am just curious what the differences are. I am wondering if the upgrades for the standard cummins are the same as the H.O. Cummins and was also wondering if the 5 speed could handle any more power going through it if one was to upgrade the motor.
 

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I'll try and get one of my buddies to post on the benefits of each one---I just don't pay enuff attention to the information on manuals like I do autos----chris
 

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word I got was the 5speed's clutch is much better than the 6 speed and the six speed will max out at around 375hp on the upgrade front--you can get more out of the 5 speed...hope this helps---chris
 

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Basically it's the same thing all manufacturers have been doing since the beginning of time. They make something that works, people like it...so they change it. Makes no sense. The 5-sp will handle the upgrades, the main problem it has is aluminum shift forks but if you don't treat it like it's a hot rod you'll be ok. The 6-sp, I don't know too much about.
 

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Ummm... the 6speed is a monster compared to the 5-speed. The 5-speed is rated for 460 ft-lbs at the input shaft, the 6-speed for 550.

Considering that I know of people in the 1000-1100 ft-lb range with 5-speeds, and no problems with their trannies, the 6-speeds will take even more.

http://www.dodgeram.org/tech/transmission/nv4500_spec.htm

http://www.dodgeram.org/tech/transmission/nv5600_spec.html

I think they figured if you want the HO, it's because you're going to use it, and if you're going to use it, you'll appreciate more gears, too.

Engine upgrades are pretty much the same. And any gains from the HO are pretty much neglible (or undone) by a good fueling box (COMP or something like that), as it's taking over the show, and you went from a 40 ft-lb increase (HO over stock) to a 300 ft-lb increase (COMP with injectors, fuel-pump mods, and intake/exhaust work).
 
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