Good evening friends; I have a off the wall tech question maybe some could shed some light on or their opinion on.
We have a 2000 Van 3500 with a 5.9 and a 4.10 rear end ratio. The rear end also is the heavy duty type that the axels have to remove to remove the drums. Im assuming this is a ton and quarter or ton and half rear end?. The van has a Pleasureway motorhome package on it so its heavy, about 9500 I think. I drive at 65 generally or maybe 69 rarely over that.
The thing is mpg is terrible, fixes and changes have resulted in nil. 10- 12.5 at best.
Here is my question; I always thought rear ends were most efficient when the engine and weight and rear ends were all matched up; ie heavy rig, lower rear end and heavy rig more engine?? So ideal this would be a good match the way we have it??
The odd part that bugs me is we have had 3 of these rigs, 95, 96 and the 2000 AND this one gets the worst gas milage by 2mpg.
Seems the rig is set at optimum. then the newer, more modern, more smog and gov stuff the worse mpg?? Isnt this what modernizing engines and exhaust supposed to help seems the gov in auto industry is like everything else??
Sorry just babbling but it sure seems like the idea of newer is better is not the case if your driving.
Thanks for the air I wasted, I feel better.
Grumpy
ps is it possible if I were running say a 3.55 rear it would be better?

 

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So, you have a:

2000 B3500 5.9L/360cid Ram Van with 4.10 rear? If so, it's a Dana rear. The Chrysler Corp rear is the 3.92. Your van may have the 3.92. If it's the Dana, there are many ratios to swap in that rear. http://en.wikipedia.org/wiki/Dana_60
Take notice if it's a Dana-60
"Dodge versions were passenger side differential drop, standard rotation gears, kingpin knuckles and 35 spline axle shafts in early models. The 2nd Generation axles were drivers side with ball joints. 30 Spline axle shafts were used instead of 35 splines, except 2000, 2001 and 2002 models which were equipped with 32 spline axle shafts."

 

I doubt you or the van would be happy with a 3.55 with the motorhome weight on her. I'd stick with the 4.10; that's what we have in our '73 class A with 440.

And yes, 10% or higher ethanol will keep you from getting better mileage. Not much choice unless you can get real gas where you are.

 

Visit the Dana Expert site to find out what your van actually has, then see what can be tweaked ... http://www2.dana.com/expertforms/demenu.aspx

Ram Vans had the Dana Spicer