With the advent of today's modern 6 speed automatics a 4.10 rear gear still only rev's 1700 rpm in high gear with a Dodge.I don't think it make's a a lot of difference any more .I liked the 4.10 for the ease of getting the rolling mass moving.That being said I've visited with a lot of people who like the 3.73.

Racerguy wrote:

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With the advent of today's modern 6 speed automatics a 4.10 rear gear still only rev's 1700 rpm in high gear with a Dodge.I don't think it make's a a lot of difference any more .I liked the 4.10 for the ease of getting the rolling mass moving.That being said I've visited with a lot of people who like the 3.73.

-- Edited by Racerguy on Thursday 29th of March 2012 02:58:00 PM

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Fred, that’s true. But it depends on the size of the tires and the ratio of the first gear of that 6 speed for the “grunt factor” required by the rear end.  That is why I suggested looking at the individual truck specifications as these are but two of the other variables that determine what rear end ratio is needed by a particular powertrain combination to move a particular load.

I agree, the 3.73 (I mis-typed above 3.76) works very nice in the Chevy's due to the very low first gear of the 6 speed.  As you implied – one size does indeed not fit all needs.  It depends.

Hope you find an RV soon.

Bill

We just bought a 2012 Ram 3500 in December. The 4.10 has a much higher GCVWR than the 3.73. Here's a link to a pdf by Ram that has the information you need. You will have to scroll to the page that has the truck that you are looking at. I'm sure you'll see how to read it. The 2500's are first but the 3500's are there too.

http://www.ramtrucks.com/en/towing_guide/pdf/RAM.2500.3500.Towing.Specs.pdf

btw, we love our truck.  Good luck!

RVKevi wrote:

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Oh, speaking of the urethra thing, the 2013 Rams are supposed to need it, so if you want one without it, the 2012 is the last year to be urethra free.

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 Is Dodge giving up on the Diesel Particulate Filter? On edit I just went to a trusted forum on Dodge trucks and they say with urea injection they can get rid of the egr and will actually get better fuel economy.They say urea injection is far better than the present system.

Tom,

Rear axle ratio goes beyond just having a higher tow capacity.  It also makes a difference on the ability to tow in difficult terrain, especially with regards to slopes on hills and mountain passes.

The numbers can be confusing for someone unfamiliar with them.  A lower number (3:73) will pull faster and with better fuel economy.  A higher number (4:10, 4:30, or 4:88) will have better towing capacity but at the expense of economy.  Our Ford F450 has a 4:88 rear end and is not great on mpg, but it hardly even knows the 18,500 lb trailer is behind it.

Terry

Byrdy,

I've been RVing about 35 years and probably will get it right soon. Anyway he's my 2 cents.

#1 If you are buying your truck for good gas mileage your in the wrong hobby (lifestyle). Buy a truck that will give you great service and do exactly what you want it to do, pull your trailer/5th wheel in a manner that makes it comfortable for you to drive.

#2 Sales people will always tell you what youwant to hear about the tow vehicles that they sell, especially if they have on the lot. Unless you have access to all the pieces to take to the scales you have to estimate a bit.

My truck is a 2006 Ford F-550 diesel with a 4.88 rear and the high capacity towing package. The registration says that it weighs 7518 lbs,but on the scale ready to go on a trip it really weighs 9710 lbs. So if I was going to buy another 5th wheel that I could not actually take to the scale, I would use the GVW of the trailer in my calculation. The GCWR of the truck is 33,000 lbs, which I think is very generous, so subtracting the truck weight from the GCWR I can tow 23290 lbs. You also have to be careful not to exceed the GAWR on the rear axle but that is hard to exceed on a modern 350/3500 since the Tetons and Royals Internationals are gone,which were the high pin weights. Hope this helps.

Jack Mayer wrote:

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Urea injection is far superior to DPF. It is more reliable, and works better.

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 Any idea how much cost it adds per mile?

VanMar wrote:

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One thing I didn't find on the GM website was what happens if you let the tank run dry!  The DIC will alert the driver when there is 1000 miles worth of DEF remaining.

It did say that DEF mileage would vary with fuel consumption.  So I guess if I'm towing a trailer in the mountains, I should cary a spare jug.

Vance

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Vance:

In the FWIW department, this DEF thing is not that big a deal.  You will get plenty of warning to replenish the DEF fluid long before speed is reduced if you run low or out of DEF.  Speed, not power, you will still have full towing power.  Take a look at the manual, available for download from the GM web site; it is pretty well explained.  But if you let the tank run close to “dry,” by law the truck will go into “limp mode” and limit your speed, not power, to a crawl.  Somewhat like you running out of gas, so don’t do that.  {Grin}  All of this is to comply with the Federal Government Regulations / EPA and we’re all going to deal with it just as we did with catalytic converters and “low lead” gas in the ‘70’s.  And as Jack said, DEF works best and it is now with us till something better, and more complicated, becomes available.

But for information, DEF has a shelf life and that life is reduced due to heat so you may not want to carry any till you have a few thousand miles on the tank.  You certainly can certainly carry a spare container, but DEF is now, in the US, readily available at truck stops, NAPA and Wal-Mart.  As long as it meets the spec, it’s all the same.  I’ve got DEF from NAPA in the truck and it has been happy for the last 4,000 miles with that product.

Just perspective

Bill