Aftermarket overdrive

[90plow]

I have a 2006 dodge 2500 cummins auto 4x4 with 4.10 gearing. Ont he highway doing realistic speeds of 75mph its revving at 2500 rpm with the red line at 3000. I don't want to get rid of the 4.10 rear becuase I like the low end. Is there any aftermarket overdrive that goes after the trans that will fit this truck? How badly would 3.88 gears in the rear affect my low end?
-Eric

[John DiMartino]

You will get used to it,Ive got 4.10 in my 2000 Cummins, i run a slightly larger tire,that knocks about 200RPM off your numbers.Im running 2000 at 70 mph or so .There are OD units,but it will take 150,000 hiway miles to repay for itself in saved fuel,really not worth it.Ill tell you this,i wasnt driving,but my truck ran from ohio to New jersey on Rt80 a few yrs back 90-95 mph the whole way,she only gets about 14-15 mpg at those speeds with 4.10's.:D

[90plow]

John I know what you mean about that fuel mileage on 80 between pa and nj I averaged 15.6 on 29 gallons of diesel. I looked at pricing and it is steep for the amount it will be run on the highway 3-4k for the setup. I think I'll jsut "have" to get a new taller wheel and tire combo :cool: I saw a setup in Diesel Power mag on a black dodge with black and chrome american wheels and Nitto Terra Grappler tires (don't know what the size was) but it looked perfect on the truck, not to big or wide if anyone knows what truck I'm talking abotu and knows the tire size let me know.
-Eric