Are you referring to a Dodge or a Chevy 3500?I am guessing a Dodge and also a diesel..No Chevy 3500 diesels have 4.xx rear ends. (Chevy’s are all in the 3.76 range.) The rear end helps determine the gross trailer / towing weight rating on Dodge and Fords among other things.Chevy diesels have one rear end ratio – no option as they don’t use higher rear end numbers to increase tow ratings due to the Allison automatic transmission.
So you want, in general, the lowest number rear end that is required for the tow rating required with naturally some head room.Super hi rear ends (like in the high 4’s) make for higher towing numbers but also kill the solo fuel mileage.Some brands are known for that.
Ask the salesman to show you the tow ratings of the different diesel trucks vs. the rear axle ratios.That should give you and idea of what I am talking about.
Hope that helps a bit. 'Trying to keep this simple at this point without making it more complicated than it is.
Bill
Edited twice to finally get the typo out. :(
-- Edited by Bill and Linda on Thursday 29th of March 2012 02:16:20 PM
-- Edited by Bill and Linda on Thursday 29th of March 2012 02:18:11 PM
Racerguy said
02:54 PM Mar 29, 2012
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
Byrdy said
08:59 PM Mar 29, 2012
Thanks for all the help. Now what do the numbers in the rear axle mean ,410 ect. How do I figure out what rear # I should get..rear wasnt a thought till saleman started rear axle 410, then couldnt put it in terms I under stood,So once again I find myself asking people I know who has been their done that
Bill and Linda said
10:15 PM Mar 29, 2012
Racerguy wrote:
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
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
Byrdy said
10:33 PM Mar 29, 2012
That is correct Bill, Dodge diesel,
RVKevi said
12:04 AM Mar 30, 2012
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.
Me too on the 4:10 rear end! I have one in my Dodge Ram 3500 - gets better mileage than comparable Ford and Chev product (this is so even w/o the urethra curse on Chev and Ford); even better than 3:73 rear ends. Regardless, the size of the rear end ultimately contributes to tow capacity.
Racerguy said
06:33 PM Mar 30, 2012
RVKevi wrote:
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.
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.
-- Edited by Racerguy on Friday 30th of March 2012 07:09:53 PM
RVKevi said
11:24 PM Mar 30, 2012
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.
Terry and Jo said
03:33 PM Mar 31, 2012
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
Rosie RV Thumper and Dog Dog said
12:06 AM Apr 12, 2012
Thank you everyone for all the information it really is great. This will help me decide what I have to do.
Fatman said
03:59 PM Jun 3, 2012
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 said
06:17 PM Jun 4, 2012
Urea injection is far superior to DPF. It is more reliable, and works better.
NorCal Dan said
10:52 PM Jun 4, 2012
Jack Mayer wrote:
Urea injection is far superior to DPF. It is more reliable, and works better.
Any idea how much cost it adds per mile?
VanMar said
11:20 PM Jul 8, 2012
NorCal Dan wrote:
Jack Mayer wrote:
Urea injection is far superior to DPF. It is more reliable, and works better.
Any idea how much cost it adds per mile?
Dan
Since I will eventually be using this stuff, I did some quick research on the cost. Cost of 2.5 gallon jug = $14 = $5.60 per gallon. Five gallon DEF tank on a GM vehicle will last approximately 5000 miles(your mileage may vary)...which equals 1000 miles per gallon which equals .0056 cents per mile.
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
Bill and Linda said
03:02 PM Jul 9, 2012
VanMar wrote: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
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
VanMar said
03:27 AM Jul 12, 2012
Thanks, Bill.
I just did quick research to find out the cost of the DEF and the estimated mpg of it. Good to know about the 'limp mode'...I was wondering about that.
Are you referring to a Dodge or a Chevy 3500? I am guessing a Dodge and also a diesel.. No Chevy 3500 diesels have 4.xx rear ends. (Chevy’s are all in the 3.76 range.) The rear end helps determine the gross trailer / towing weight rating on Dodge and Fords among other things. Chevy diesels have one rear end ratio – no option as they don’t use higher rear end numbers to increase tow ratings due to the Allison automatic transmission.
So you want, in general, the lowest number rear end that is required for the tow rating required with naturally some head room. Super hi rear ends (like in the high 4’s) make for higher towing numbers but also kill the solo fuel mileage. Some brands are known for that.
Ask the salesman to show you the tow ratings of the different diesel trucks vs. the rear axle ratios. That should give you and idea of what I am talking about.
Hope that helps a bit. 'Trying to keep this simple at this point without making it more complicated than it is.
Bill
Edited twice to finally get the typo out. :(
-- Edited by Bill and Linda on Thursday 29th of March 2012 02:16:20 PM
-- Edited by Bill and Linda on Thursday 29th of March 2012 02:18:11 PM
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
Thanks for all the help. Now what do the numbers in the rear axle mean ,410 ect. How do I figure out what rear # I should get..rear wasnt a thought till saleman started rear axle 410, then couldnt put it in terms I under stood,So once again I find myself asking people I know who has been their done that
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
That is correct Bill, Dodge diesel,
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!
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.
-- Edited by Racerguy on Friday 30th of March 2012 07:09:53 PM
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.
Any idea how much cost it adds per mile?
Dan
Since I will eventually be using this stuff, I did some quick research on the cost. Cost of 2.5 gallon jug = $14 = $5.60 per gallon. Five gallon DEF tank on a GM vehicle will last approximately 5000 miles(your mileage may vary)...which equals 1000 miles per gallon which equals .0056 cents per mile.
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
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
Thanks, Bill.
I just did quick research to find out the cost of the DEF and the estimated mpg of it. Good to know about the 'limp mode'...I was wondering about that.
Vance