2013 Dodge 3500 DRW Gear Ratios

[LvOpnRd]

Hello everyone.

The wife and I just purchased our first 5th wheel a few weeks back. It's a 2012 Forest River Sierra 345RET. It weights about 11,000lb dry. For a tow vehicle I'm looking at a 2013 Dodge 3500 Mega Cab DRW.

My question has to do with gear ratios. Should I go with the 3.73 or 4.10? The majority of our towing will be done on Highways across Eastern Canada and I will also be using this as an everyday vehicle when not pulling the 5th. We are going out west this year for the honeymoon but that's just one trip in the mountains. I'm leaning towards the 3.73 but thought I would ask around first. I don't see us going any bigger than this trailer we have now.

Thanks in advance.

[cummins2014]

RedAce wrote:
I think you are right to go with the 3:73s. Unless you do a lot of highway driving at 50 to 55 mph, in which case the 4:10s might be better. We pull a 15,500 GVW Montana with our CTD dually with the 3:73s. No problem.

This is crazy being told 4:10's sure there is a place for them, big reason in the dually's is that they are capable of more weight, by the time you need 4:10's in a SRW you are already overloaded.

[cummins2014]

ah64id wrote:
Your getting a dually for weight, or else you would be getting a SRW. 4.10's are for weight, everything else is a compromise.

up2nogood wrote:
My exact thinking, have no desire to see how fast I can come off a stop light,3:42 gears will do just fine with the power of the new cummins

It's not about coming off the light fast, it's about the 20% more torque you get to the rear wheels with 4.10's than 3.42's for the same engine output.

It's less stress on the trans and engine for the same power to the ground. For 3.42's or 3.73's to put the same power to the ground (where you need it) the trans has to drop a gear to get the torque multiplication, more heat/stress in 1 place instead of spreading it out.

rhagfo wrote:
I have reader into your responses that you have never driven a diesel truck. The low end tourque is awesome! With my old 5.9 even in low speed city driving I very self ome need to shift.

Yes low end torque is awesome, maybe it's where I live/tow but there are many times I wish my 05 had 4.10's winding up a 6-8% grade at 4-8K feet. 3.73's are a good all around gear, but the extra 10% at low speed is very helpful. That's with more hp/tq than the newest 6.7 makes...

Many people thing Dodge made a mistake only offering 3.42's in the SRW trucks, when towing heavy it compleatly negates the 6th gear. Why build a truck that won't use it's top gear towing? If you want to make 3.42's the norm then trade the extra OD for a gear in the middle with a lower 1st.

Again, probably because I never tow on level ground.

I never had problem, never knocked out a tranny ,never blew a motor with 3:73's , with an old ford 7.3. Now you are telling me I am going to ruin things with this new cummins, thats pretty funny completely negates 6th gear, I know several guys towing heavy with 3:31 ,and never getting out of 6th unless pulling the mountains, and you think that cummins with 3:42 are going to be any different. The ford running @ 70 was right at 2000 RPM pulling in the top gear fourth, this cummins without really checking it yet is going to be pretty close to the same RPM in sixth gear @ the same speed, and with nearly double the torque ,and horsepower .

[RedAce]

I think you are right to go with the 3:73s. Unless you do a lot of highway driving at 50 to 55 mph, in which case the 4:10s might be better. We pull a 15,500 GVW Montana with our CTD dually with the 3:73s. No problem.

[retispcsi]

Well I have at present a 2012 Ram 68re DRW Max Tow 4:10. Previous truck was a 2003 Ram47re SRW 3:73. I still pull the same trailer and I use the truck as a daily driver. I live in Fla. which is pretty flat. But I tow everywhere, flats hills, mountains etc. I get about the same MPG towing with the two vehs. The 4:10 is awesome when climbing and the low end torque well that ain't bad. My point is and this is my two cents the 4:10 with either auto tranny is the way to go. My next Ram will also have a 4:10 it is such a nice gear with the auto trans. My two cents worth, but go out and drive the trucks geared differently and see for yourself.

[AH64ID]

Just did some quick math on the subject.

Lets assume pulling a grade at 55 mph using max torque and a flat value of 800 since I can't find the actual curve.

4.10's in 4th (direct) is 2450 rpms. 800*1.0*4.10 = 3280 ft/lbs to tires
3.73's in 4th is 2200 rpms. 800*1.0*3.73 = 2984 ft/lbs to the tires

So assuming that the 3.73 truck can hold 2200 rpms with 800 ft/lbs the 4.10 truck could decrease the power output to 2984 ft/lbs at the wheels or 727 ft/lbs at the motor. Less power means less fuel, less heat, and less stress.

Both trucks can do it, but which one is doing it easier?

There is no doubt that the 3.42 and 3.73 truck can pull like no tomorrow, especially compared to several year old trucks... but if your going to do it, do it right.. just my 0.02.

[AH64ID]

Your getting a dually for weight, or else you would be getting a SRW. 4.10's are for weight, everything else is a compromise.

up2nogood wrote:
My exact thinking, have no desire to see how fast I can come off a stop light,3:42 gears will do just fine with the power of the new cummins

It's not about coming off the light fast, it's about the 20% more torque you get to the rear wheels with 4.10's than 3.42's for the same engine output.

It's less stress on the trans and engine for the same power to the ground. For 3.42's or 3.73's to put the same power to the ground (where you need it) the trans has to drop a gear to get the torque multiplication, more heat/stress in 1 place instead of spreading it out.

rhagfo wrote:
I have reader into your responses that you have never driven a diesel truck. The low end tourque is awesome! With my old 5.9 even in low speed city driving I very self ome need to shift.

Yes low end torque is awesome, maybe it's where I live/tow but there are many times I wish my 05 had 4.10's winding up a 6-8% grade at 4-8K feet. 3.73's are a good all around gear, but the extra 10% at low speed is very helpful. That's with more hp/tq than the newest 6.7 makes...

Many people thing Dodge made a mistake only offering 3.42's in the SRW trucks, when towing heavy it compleatly negates the 6th gear. Why build a truck that won't use it's top gear towing? If you want to make 3.42's the norm then trade the extra OD for a gear in the middle with a lower 1st.

Again, probably because I never tow on level ground.

[rhagfo]

I have reader into your responses that you have never driven a diesel truck. The low end tourque is awesome! With my old 5.9 even in low speed city driving I very self ome need to shift.

[transamz9]

I have the same fifth wheel and pull a 4500# boat behind it and have been doing just fine with my 3rd gen and 3:73's. My new truck has 3:42's with the Aisin SRW.

[cummins2014]

LvOpnRd wrote:
I'm getting the sense that because I'll be doing a whole bunch of driving on the highway without the trailer that a 3.73 might be a happy medium.

My exact thinking, have no desire to see how fast I can come off a stop light,3:42 gears will do just fine with the power of the new cummins

[AH64ID]

LvOpnRd wrote:
We won't be going any faster than 70mph or 110 Kms.

4.10's, if you do any windy mountain driving you will appreciate them.

The Aisin/4.10 combo should also hold a higher resale.

Why get "good enough", or "it will work", when you have the ability to get the best towing combo on the road.

[LvOpnRd]

We won't be going any faster than 70mph or 110 Kms.

[Bionic_Man]

I tow about 17000 pounds with my 2012 and fell that the 4.10 are overkill. I would go 3.73 or higher if I were buying today.

[AH64ID]

LvOpnRd wrote:
I'm getting the sense that because I'll be doing a whole bunch of driving on the highway without the trailer that a 3.73 might be a happy medium.

At what speeds?

[cummins2014]

Had 3:73 in my old Superduty 7.3 did a pretty good job towing 12K, but it just didn't have the power the new ones have. I may be wrong ,but the new SRW ford diesels are 3:31, and my new 2014 Ram SRW 3500 has 3:42 gears, have not towed yet, but I don't anticipate any issues, lots of trucks out there with these gears

[LvOpnRd]

I'm getting the sense that because I'll be doing a whole bunch of driving on the highway without the trailer that a 3.73 might be a happy medium.