I just drove a 2010 SLT 4X4 Big Horn and really liked the truck. Max acceleration may have bit a bit less than the Tundra but that isn't a big deal.

I really liked that at 60mph the tach was indicating something like 1,500 rpm. Much to my surprise the window sticker indicated the truck had the 3.92. I don't tow all that much so I don't need the 3.92, but this truck drove so nice I think I may want to go with it. My sales guy said the MDS trucks can get 22 on the highway straight cruising and this is a big improvement over a Tundra's sticker of 17 and the Ram's own 18.

So long story somewhat short, does the 3.92 make a noticeable difference at the pump or not so much? I have read the thread on fuel economy and it looks like the way the truck is driven has a lot more to do with mpg than just the rear end ratio.

NC

 

I'm driving 50/50 city/hwy daily and I get no better than 15mpg.

 

I have found with regular unleaded (87) is my best mpg. I see 14-15 city and 18-20 hwy. I see less mpg with the other grades of fuel.

 

Thats odd, I have the 3.92's and at 60mph I am reving at just below the 2000 mark......

Dario

 

Yeah I find it hard to believe that it is only running 1500 rpms at 60 mph. I have the 3.55 and that is exactly what i run so I'm betting it had the 3.55 rear end and was mismarked.

 

If I can remember I'll take a look tomorrow at 60mph and letcha know.

 

It could have been 1,750 but I am real certain is was well below 2,000. Now maybe I happened to look down while I was coasting at 60 and the rpm's sagged a bit.

Either way the RAM is one nice truck. I wish it came with the backup video camera like the Tundra. That will be nice for trailer work come summer. I can probably get that on a higher trim level RAM but the Big Horn is pretty complete and affordable at an MSRP of $36,500. The way the rear seats fold and yield a flat cargo deck is a pretty nice feature as well.

NC

 

I have the 3.92's. My buddy has the 3.55's. I get slightly better mpg's. Of course this could be due to driving style, etc.
But we both have 20's and I personally think 3.55 is too tall for those tires.
BTW, we both get around 14-18mpg running on 87 and I have the MDS disabled.

Sorry, just noticed I posted in 4th gen.
Might still be relative tho, dont know much about 4th gen. yet.

 

I have 3.92 gears in a 2wd sport addition and with a combination of city and highway driving the truck averages 15 mpg. The best the truck has ever gotten on the highway is 18 mpg and mostly hovers around 17 mpg. The 3.92 gears are great for towing and a friend of mine has 3.55 in his truck and the torque converter seems to hunt around on the highway. Keep in mind the 3.92 rear ends normally also include the limited slip diff. so to me it is the best combination. Good luck with your decision.

Chevyave

 

I have the TRX4 with the Hemi and 3.92 gears. On the interstate with no wind I can get up to almost 18mpg at 70-72 mph. At 65mph it'll get almost 19mpg. This is on flat roads with no wind.