"joelb7" wrote: > It's an Automatic and it has the Stock Michelin Tires on it. > I also got a Snug Top camper shell trying to make the truck > more arrowdynamic > It's a 2004.5 Top of the line Leather 4x4 all stock > I have a friend with the same truck and he gets about 5 mpg > better > I really think something is wrong I mean come on 10 MPG city > 14 hwy (going 75-80) > Joel
diesels have a sweet spot of sorts RPM wise where they do there best but that aside 14 MPG at 75 to 80 is not far off for a big truck like that with a deisel. If you drop to 65 to 70 it will likley increase a few MPG towing and not. A few things you can try, when towing do not lug the motor, keep it above 2000 RPM when pulling hard but under 2500 on long pulls, above or below that speed MPG can suffer when pulling hard. Also make sure you have got your tire pressure up and that helps (my buddy gained 1.5mpg on hiway with his Dmax when he increased tire pressure from 45 to 65 to 70psi on his crew cab 4x4. Also, something else you are fighting on a Dodge is that they did away with the front axle disconnect in 03 so you are ALWAYS dragging the front axle with you (axle shafts, drive shaft and diff) even in 2wd This can cost you
1MPG or more on highway because it consumes several HP as hiway speeds. Dodge really screwed up on this one because they had a whole new axle designed for 03 and left out the abilty to even add lockout hubs which was really dumb. You might try changing your front and rear axle lube with fresh 75w90 (SYN if you want) and that may get you another MPG on hiway. I have seen fresh axle lube perk things up a bit especailly if it has not been done for a while. And in closing, a 3.73 with a automatic is a bit tall to tow in OD at times so MPG may suffer if you pull it hard. I have driven several Cummins truck automatic and manuals and they seem to run best with a stick with a 3.73 and with a automatic with 4.10?s because the automatic carries a taller OD ratio than the 6speed does. It is a nice engine for sure, just need to load it properly RPM wise if you want maximum work with minimum fuel consumption.