Hey guys, so i've decided on a 5.9CR cummins. I can still find them with 50,000 miles which despite my gut says thats a lot, I KNOw for a cummins it's nada ( i sold my 12v with 189K)

I am looking though, some have a 4speed auto, some a 5 speed auto, and soe a 6speed manual what gives?

I like the manual because there isn't too much damage they could have done prior to me owning it besides the clutch, which is cheap compared to a new auto.

BUT i like the thought of going back to an auto, since its a CC long bed, and auto would be kind of nice.

So what is the deal with with the 4spd vs 5 spd? Pro's cons? MPG? reccomendations....I need info. How to tell what has which tranny? ( VIN CODE )

thanks for the info guys.

 

always get the manual the handle upgrades way better less complex i know three guys with autos and they all have some sort of issue my brothers 03 has a little slip to it he just waiting for it to pop then hes gona get the 5k ats tranny 139,000 miles my buddys 05 als has a little slip to it his truck is stock with 125000 i think they are both 4 speeds. dodge is notorius for there shity autos get the 6 speed and youll never need to buy another truck in ur life and its more fun anyway

 

There are no 5 speed autos in these trucks. The auto is a 4 speed, there are two 6 speed manuals, and one 5 speed manual.

The early 2003 SO's were available with an NV4500, very rare bird. (5 speed manual)

Early 2003 SO autos were 47RE. (4 speed auto)

2003-2004 HO were NV5600 (6 speed manual) or 48RE (4 speed auto)

2004.5-2005.5 were NV5600 (6 speed manual) or 48RE (4 speed auto)

2005.5-2007.5 were MB56 (6 speed manual) or 48RE (4 speed auto)


Automatic OD gear is .69

NV5600 OD is .74

MB56 OD gear is .79

Standard gear ratio is 3.73, 4.10's wer optional but they could be there.


Needless to say, unless you are towing heavy all the time the manuals are at a big disadvantage in the gear department. Slow shifting, low geared, low mpg. Add to that all the later trucks from 05.5 on has the infamous DMF which is about as strong as the stock auto TC.

Advantage 48RE from 05.5 forward.

The best setup was the NV5600 without DMF. Unfortunately that trans is out of production, if you beat on it shifting it broke, and parts are way expensive to rebuild it. The MB56 is a nicer shifting trans that is available but the OD gear kills efficiency unless you drive a maximum of 60 mph. Advantage still 48RE.

The 48RE is a solid transmission that will give good service if you understand how it was setup for the Cummins and what was done to make it NVH compatible. Ignore that and drive it like a sports car, power up the engine without addressing the trans (yes some ofthe less astute REALLY do that), and it will give you problems. Drive it like a powerful heavy duty truck and it will last longer than any diesel auto in that type of truck.

The auto is dead easy and simple to upgrade to handle just about anything you want to do. Its the same as anything else, how much $$ equate to how fast you want to go. There are many choices and levels of upgrading and it can be done in stages with excellent results.

 

sounds like he knows more than i do but all i know is i would not buy a auto for any reason if its in a dodge because ive never seen one that works right no mater what the auto guru says above me THE AUTOS SUCK period thats why the 6 speed trucks cost a little more cause there the way to go besides he probly owns a transmission shop and loves broken trannys plese get the 6 speed o yea and ive never seen a 6 speed swaped for a auto have you

 

yea i have seen it done many times. if it was me i would go with the nv 5600 6 speed if you can find one. they are a tough tranny. either way though is a good choice its all in what you like

 

About 50\50 on the swaps. Depends on what a person wants to do and what they need or if they made a mistake with the manual. There are a LOT of people that would not own a manual for a variety of reasons.

They have their uses like I pointed out. I have 4 trucks with upgraded autos, wore one out with over 250k, and over powered another one testing its limits at over 100k. The rest are still motoring on with lots of miles.

 

I have owned 4 dodge diesels, an 03,05,06, and currently have an 07. Every one of them a 6 speed. Personal preference really. Both can be very good and very bad depending on what you do with it. I know the nv5600 is supposed to be a better 6 speed but i'll take the g56 any day. Much smoother shifting and I like the low OD. Never have to downshift to pass cars pulling a big load on the highway. My neighbor has an 03 auto and pulls a 12k 5ver quite often and has over 100k on the truck and it shifts like brand new. My cousin as an 08 with the G56 and is currently replacing his 3rd tranny for it with under 25,000 miles (major abuse on his part) He runs it like a vette with 13" of lift and 38x15.50 tires. Like I said everyone will be bias, but both have there goods and bads. It really all comes down to if you feel like shifting gears or not. Hope this helps you.