I test drove a 2007 3500 4x4 with 3.73 gears and loved the truck. The problem I have is that I will want to put a 35 " tall tire on it. The engine RPM is 1900 at 75 mph so I figure it will drop to about 1600 with a tire that tall. Of course the Dodge salesman says that all is good and the truck won't even feel the difference. Should I look for a truck with 4.10's ? I will be putting a slide-in camper on it and towing a smaller trailer with camping "stuff" on it. I would even consider a 37 " tire if I needed to get the rpm in the sweet spot for this engine. My '02 likes 1900 or so for highway cruising and that equals 75 mph with my setup.

 

I would go with the 4.10's . I had 35's on my 07.5 with 3.73 and it killed my MPG. Dropped it on average 2-3 mpg, Also it was harder to turn and now i see my power steering pump is leaking I have about 30k on the truck. There is a pretty fair drop in power with the set up i had. 4.10's would work out about right.

 

I have 37's on mine with 4.10, I'm right at 2k running 70.

I don't think it will drop that much. Could be wrong, but that's a lot.

 

My bud has a 2010 with a 68RE / 3.73 and just put 35's. Didnt even notice a difference other than the speedo being off.

 

Thanks for the input, my gut says that I should go with a set of 4.10's also. The 68RFE's double overdrive is the big help. I don't want to get a truck that is set up for maximum mileage and then compromise my ability to tow at a later date. It is good to get some real life backup for my decision.

 

I tow a 28' travel trailer (9,000lbs loaded) with 315/70/17 (35") tires and 3.42 gears. No Problem. The 6 speed auto makes it easy. Lots of power. The low first gear gives me great get up and go power. Even with the bed loaded with gear and the trailer hooked up, the tires still tend to spin if I mash on it and the road is wet.