I'm new here and going to be purchasing an HO Qd Cab 04 with the 48R trans. I'm am trying to decide what rear gear to go with for highway driving. Could you guys out there tell me what your RPM's are at at 70 MPH with 3.73 and 4.10 gears your help with this is greatly appreicated. <br><br>pat

 

I just got my 03&quot; H.O. with the 48RE and 3.73 gears. At 70mph I turn just about 1900 rpm's. This is with the off-road tires. With 1/2 tank of fual and almost 300 miles I am averaging 17.6mpg (varying the rpm's...over 2000 and under 2000) for the break-in.

 

Go with the 3.73s. Your mileage will be better and you'll have plenty of towing ability. I love my Quadcab and HO engine. It is an awesome ride.

 

I have 4.10s and at 70mph I am somewhere around 2200 rpms.

 

From Angleiron's post, 70 mph at 1900 rpms isn't bad. If you want to go even lower, I read where American Axle does make a 3:54 gear for their differentials in the '03 Ram Heavy Duty. I wonder why Chrysler didn't offer this ratio?<br>

 

3.73 HO 6 speed, at 70MPH, 2050 RPM with no load, about 10 MPG<br><br>Hunter

 

I got the HO/48re with 4.10's because I have a heavy trailer behind it 90% of the time. 2200 RPM's at 70. About 16mpg is all I can squeeze out of er empty but it is not broken in yet. My grandpa has the same truck with 3.73's and he is averaging 19.5 highway mpg.