3.73 or 4.10 for my trailer weight?

[Dieselnerd]

This coming week my order goes in for a 2005 3500 SRW 4x4. The max gross weight of my fifth wheel is 13,900. It normally weighs around 13,000-13,500 on the scales loaded for my winter trek to the South. My current truck has a 4. 10 axle and works fine for this trailer. When I get another fifth wheel it will probably be a similar weight. I am torn between the 4. 10 to give me a nice towing margin or the 3. 73 which will be right around maximum towing weight. I am leaning towards the 4. 10 but want to hear from real world experience with the 3rd gen trucks. Thanks...

 

[Casey Balvert]

I chose the 4. 10 in both this truck and my last truck which was a 97. If you follow DC's recommendations you will be right at the borderline between the two ratios for the combined weight. Since trailers seem to be heavier than we first estimate, I recommend going with the 4. 10 for the extra 2000 pounds of GCWR. I don't regret my choice at all. Yes, there is a slight fuel economy penalty but unless your foot is always in it then it really is not even a concern. However keep in mind that with a 14,000 pound trailer, your pin weight will be very close to 3000 pounds and you will exceed the GVWR of the SRW 3500. Your truck with passengers, full fuel, hitch and accessories will probably weight close to 8,000 leaving you 1,900 for payload. You will be over by close to 1,000 pounds. You are definitely over with your current truck but you don't need me to tell you that. FWIW



Casey

 

[Bertram65]

If you are getting the auto get the 4. 10s, if you are getting the 6 speed get the 3. 73s, they work out close to the same final drive ratio. The 4. 10s with 6 speed rev real high at highway speed limiting running empty speeds, the 3. 73s with the auto in my opinion rev to low for towing at highway speed, the spread between 3rd and OD is pretty wide so dropping down really limits your speed. With the auto and 4. 10s you are at 2150RPM in OD,at 70MPH towing heavy anything less than 2000RPM you will not have the power to pull long steep grades and have to drop down.

 

[BigEasy]

a 13k trailer seems awful big for a SRW...

 

[crobertson1]

I vote for the 4. 10s.

 

[klenger]

Unless you are planning on driving mostly empty, I'd get the 4. 10s. The MPG difference shouldn't be all that much and the 4. 10s handle the weight a lot better.



Interesting in meeting up when you get to Tucson?

 

[juicedcummins]

Take out a set of 410's and drop out the overdrive @highway speed . Go with the 373's and drop a gear if you have too. The only place 410's belong is behind the v8's. I run @ 22k loaded with 355's and 265 tires without even braking a sweat including running the Canadian rockies. With this kind off weight I run with the box off around 520tq. That is a lot less than todays models. These engines may take the high rpms but they are still an inline 6cyl.

 

[Perrysburg_Dodgeboy]

3:73 Gears will do you fine, remember your getting 610 foot pounds of torque.

I’m sure you will do some mods. exhaust, air filter and maybe a controller. I’m running the 3:73 but not with the weight you’re hauling. The difference in mileage should not come into play (2 mpg is the difference between the two gears). The longevity of your truck is what you should look at. I’m running 1800 rpm’s @ 70 mph. the 410 guys are running 2350 rpm’s @ 70 mph. the higher you run your rpm’s the shorter you engine life will be. I would put the duel wheels under it at that weight though. Oo. One last thing, do you know anyone that works @ DC so you can get the friends and family discount? If you don’t send me a e-mail and I’ll give you one so you can get a little more off the price. Every penny counts.

2004 2500 QC/Auto/3:73/4" SS Ext/Prodigy

 

[rideon]

4.10's

I had doubts about the 4. 10's until I pulled my 35' toy hauler. went to 285 tires instead of 265 tires.

wouldn't change anything.

 

[wyosteve]

My . 02 is that you should decide gear ratio based on the type of driving you do the majority of the time. By that I mean, how often or how many miles per year will you be towing that trailer versus running empty. If empty more than towing, go with 3. 73's. If towing more than empty, go with 4. 10's. I tow as much and occasionally more than you do ( in weight that is) and have no trouble maintaining speed on hills even at altitude. fwiw

 

[Rockcrawler]

A lot of good stuff covered- what a lot of people fail to discuss... . What speeds are you running? Are you in a congested area where the posted limits are 55-65? Or are you running in 70/75 territory? I've only got manual transmission experience first a 5, then a 6- both trucks were mildly bombed, a little bigger tires and 3. 54's and now 3. 73's. no regrets, about 20-25 k towing a yr, elevation, winds, steepgrades. seems like 17-2200 is the sweet spot, lots of times I'm looking for one more gear

 

[NIsaacs]

You haven't said what transmission you are thinking about, if it is the 6-speed, go with the 3. 73's. The Cummins likes to run on the slow side. If it will be the auto... ... ... . ???



"NICK"

 

[Dieselnerd]

You're right Nick, I never mentioned stick or auto, my oversight. Automatic for sure.

 

[Bertram65]

Get the 4. 10s with the auto.

 

[JBotz]

I just got 05 4 door drw with 3. 73 and auto. pull 32' SRV toy hauler. works great. towed trailer with old 91 dodge with 3. 07 gears from buffalo to benson AZ. If you have the power gears are not a prolbem.

 

[Matt400]

Going with the Auto looks to me like 3. 73's would be fine if you don't tow in OD. If you want to tow in OD then 4. 10's for sure. Also if you want bigger tires then 4. 10.



I tow 6K in OD on the flats just fine and really like the 3. 73's when unloaded.

In the mountains and below 55 mph I switch OD off.



To further narrow your decision let us know what size tire you will use and if you tow in the mountains.

 

[Dieselnerd]

Thanks for all the thoughtful answers and opinions. I do tow heavy in the mountains and have always had 4. 10 gears in various trucks including my present Dodge TD. I had hoped that the '05's with the higher power might get by with 3. 73's and it probably would but I also wanted to be within the factory tow rating of the truck. Since I first posted I did a lot of research at the Dodge towing site. The 3500 4x4 SRW with 3. 73 gears is rated for a max trailer weight of 13,750. The GVW of my current trailer is 13,900 although I don't run it quite that heavy. The same '05 truck with 4. 10 gears has a max tow rating of 15,750 which gives me a large safety margin and also allows for a slightly heavier trailer in the future (they never seem to get lighter). Based on that, I have decided to order the 4. 10's.

 

[Prairie Dog]

I'd vote for 4:10's with that much weight.

 

[mbadger]

I pull a 30 ft. 5th. Wheel trailer and a boat behind that with my 4. 5 Dodge with 6 speed and 3. 73 rear end and have had no problem.

 

[klenger]

Good decision Dieselnerd. You will be pleased.