Hi, just joined the forum and glad to find the knowledge base that exists here. I haven't owned a Dodge or a diesel or a large truck before and I am seriously considering a 2010 Ram 2500 Cummins crew cab short bed. I don't have a pressing need for the truck but I want a diesel and have been waiting for one to show up in a large SUV but that doesn't seem to be happening. I would use the truck primarily for towing a small travel trailer (under 6000 lbs) or one of my boats (which are all under 5000 lbs). I currently use a Yukon Denali and it does fine but on steep mountain passes the diesel would excel I am sure. My question concerns axle ratios, the 2010 2500 now offers a 3.42 ratio that I think would be low enough to tow the relatively light loads that I tow and maybe more fuel efficient when not towing. I can't find out much about the different ratios from Dodge or from dealers as they all seem to stock the more popular 3.73 (which is the highest available in 2009 I believe). Does anyone have an opinion on the 3.42 axle ratio? I think with the low end torque of the Cummins this higher ratio would work well. I realize it would limit the size trailer that could be easily towed. thanks, Ed

 

Are you looking at a stick or auto? 3.73 for the auto and 3.42 with the manual. You will be fine with those. They also offer 4.10 gears for the auto for heavy haulers. I am not sure if you can even get the 3.42 gears with the auto tranny.

 

I'm looking at the 6 speed auto, the 3.42 is available with it. I agree that the 3.73 would be fine, but I was thinking the cummins should pull the taller gears with no problem and possibly result in better mileage??

 

i have a 6 speed and 3.73 antispin love it i'm runnine 34 in tall tires 1800rpms at 65 the 3. 42 might be a little week. if you grab a heavy load once in a while . robbie

 

For 2010 my understanding is they are offering a 3.42 gear set below the 3.73and higher 4.10.

If you ever tow moderate loads in a mountain grade environment, I would go with 3.42 gears. Fair balance between fuel economy and performance.

My 2 cents.

 

I ordered my 05 with 4.10's knowing that 35's were going on shortly after I got it. Now looking at the 2010's. Personally, I won't even consider the 3.42 option. Just makes the whole package feel rather lethargic. I already test drove the '10 with 3.73's and it didn't exactly feel too peppy, but I'm comparing it to my '05 which is modded somewhat. I'd go for the 3.73's.....

 

Pulling good size loads with an auto and 3.42 gears won't help the longevity of the tranny, that's for sure. Another thing, you will be lugging that thing around so much you may have DPF issues. These trucks are meant to tow, not putt putt around in.

 

thanks a lot for the opinions Spooler and others, sorry to be such a newbie here but what is DPF? I have tried to get some opinions from Dodge on these axle ratio options but they seem to have no opinion they are willing to share. I also am disappointed with the online specs, they are incorrect (e.g. overall length, wheelbase, turning radius) at least for the crew cab short bed and they can't seem to get them corrected. Thanks again for the comments. I would like to know what the rpm is for a speed like 70mph for both the 3.42 and the 3.73 -- I'm sure Dodge has the info to calculate that but they are not willing to so far.

 

diesel particulate filter

 

I finally got to drive one of these monsters -- I loved it. It was a 2500 Big Horn short bed with the Cummins (of course) and the 6 sp automatic. It had a 3.73 --- and I thought it was very responsive -- more acceleration than I expected. Makes me continue to ponder the 3.42 ratio since I will only be towing part time and 6000 lbs max. The truck was showing 1750 rpm at 70 mph and 1500 rpm resulted in 62 mph (approx based on my ability to read the tach and speedo) in 6th gear. If my math is correct (not sure) that would mean 70 would be about 1600 rpm with the taller 3.42 ratio. I do a lot of towing at 60 to 65 mph which would be under 1500 rpm with the 3.42 gears. What is a good rpm to "cruise" at with a light tow load to optimize engine life (not lug the engine) and fuel usage? Is below 1500 a problem? Of course I could lock the trans in 5th gear while towing to increase the rpm some. Lots of options, too many choices. I did speak to a Dodge engineer in the commercial truck group (via phone), he suggested the 3.42 with my tow weight and said the 3.73 is not needed with the low-end torque the Cummins has. Ed

 

I went with the 3.42 and a stick.

My 2003 is a 3.73 with a stick and I would gladly trade 1st gear for a 7th. You would need to be attempting to rip your house off its foundation to actually "need" first gear on this truck. I spend a lot of time on the highway and could easily make use of a 7th gear.

You won't even know you boat is back there regardless of the gear ratio you choose.

 

3.73 with 315 tires will net you a 3.52 rear end.
This is, in my opinion, the perfect gear ratio for light towing....7,000 lbs and under.

RJ

 

I will probably not change from the stock tire size. I agree the wheels/tires look on the small side in those huge wheel wells but I don't want the truck any higher off the ground (I know lots of you lift these trucks higher than they are but my serious off road days are over and I had a '77 Bronco for that.). As it is now I think I would almost need a step ladder to wash the windshield and it is quite a jump for the dog to get in the bed. So based on your analysis which I agree with, 3.42's remains a viable option. Just for information, does anyone know approximately the cost (how much labor etc.) is reqd to change the gear ratio on a 4x4 like this? Is it a difficult job, I would guess there would be need to reprogram some things.

 

I changed the clutches and steels on mine...but would not feel comfortable doing all the set up angles, etc. on a full replacement.
So I got a quote for changing my 4x4 to 3.73. Roughly $750 for parts and $700 for labor.
That was on a Dana 70. I suspect A&M might be more.

RJ

 

i just put 34x11x20 tires on my truck and they fit and look perfect IMO.