I have come from another universe in time to greet you. I started working on diesels in 1963 at my dads trucking co. A fleet of Diamond Reo stubs with 225 Cummins. Now at 59 I have 2 MB's, A 90 350SDL and a 85 300CD I run on vegtable oil. Just purchased a new 2006 (yes, 2006) 2500 Cummins from Dodge dealer. The price was right. Don't want power, power, power; just want fuel economy. I will not be towing, just putting a camper top on for vacation trips. The truck has a 6 spd, I use 2, 4, 6. All gears seem one gear too low. It has an 11.5 ring and 3.73 ratio. I see AAM has come out with a 3.42---I'd love to see a 3.08. The questions are (remember, I'm a cheap old edited by admin):

1. Anybody make just an ecconomy chip.

2. Is 3.42 the best I can do on a rear end. Can't justify an OD unit.

3. Is any one out there running on of these 3rd gen pressurized rail units on WVO. I don't plan on doing this till the warranty expires. My old MB's run fine on it but things were simpler back then. Thanks.

 

I have almost the same set up but a 2007 with a 5.9, 6sp etc.

My plan is to go up in tire size to 315's/35's, run synthetic motor oil (10%increase mpg) and maybe gear lube and add a manual locking hubs (another 10% increase mph).

Right now Im getting approx 17mpg on average and hwy has got to be over 20mpg i just have not checked that yet. The over head after a reset reads some crazy mpg numbers like 24mpg to 26mpg.

 

You're not cheap. You are already talking about buying chips and rear ends. I used that same excuse when I was your age.

Welcome !

 

1. I don't know much about the chip, but there are a couple downloaders / programmers out there that have had some decent MPG gains posted. From what I've seen, The superchips flashpaq 3805 is said to have some good MPG gains as well as a Smarty CR.

2. AAM has only recently come out with the 3.42's. I haven't seen any better gearing than that. Maybe there is another ring and pinion set that is coincidentally compatable, but I don't know of any. I can't justify an OD unit myself...yet

3. I can't help you on WVO. Sorry, Haven't done enough research on it.

 

i get 16 in my 07 at 54k on the motor and i run the triple dog, the 3.42 gears shouldnt be to expensive got a quote for a set at 800 and thats for fronts and rears