Valv

Did most of the 3500s auto came with 4:10 or is there a significant amount of 3:55s out there ?

country ...boy

I cant say how many came with what but mine has 4:10s and the fuel milage to prove it. Its milage is still better than any gas truck I have had , I would not want any higher of a gear [3.55] for towing with an auto.

dozer12216

Large number have 3.55. For reasonable highway towing, can't imagine using 4.1 ratio. Off road or really heavy towing in mountains would be application for 4.1 IMHO

Grease Monkey

I had 4.10s in my 12 valve, they are pretty much useless unless your using your truck as a tractor or a bulldozer. JMO I have 3.55s now and will never have another truck with 4.10s.

Erska

4.10's are perfect with 37x12.5 " tires.

Pretty much the same ratio than 3.55 with 285/75 R16 tires.

blackdiesel

Dad's 02 3500 has 4:10's and my 02 3500 has 3:55's, so I'd say that it's 50/50. We like my truck to pull a trailer with. You really need it if your pulling at higher speeds (60-70). And I get about 19-20 mpg on the road and Dad gets 15-16 mpg. Around the farm we both get in the 11-12 range.

CoastalDav

If your going to tow 10k or more, you need the 4:10's. If less 3:55's will do it.

I have 3:55's. Sometimes I wish I had 4:10's but for now, I do more running without the trailer. When towing I suffer with 10.5 mpg or less because I can't get the engine up in the RPMS were it needs to be for better mileage.

You need to be around 2200-2300 rpms when towing heavy so the engine is really off load, so to speak. With the 3:55's the engine is loaded all the time. Normal towing at 65 is around 1800 rpm's. 4:10's would be around 2200. Less load and more fuel mileage.

Dave

blackdiesel

everybody says "oh if your towing over 10k you NEED 4.10's" and thats the biggest load of BS that i've ever herd. The only thing that lower gears are good for is to get the load rolling. And first with my 3.55's will get anything moving that you can pile on our 32' trailer.

If you need more rpm's out on the road, drop down to direct drive.

CoastalDav

Well, I guess you must be talking to me. I do use 5th gear when the speed limit is 55 when towing my fiver. Mileage increases to 13.5 on the as you drive
mileage indicator in the overhead. I wonder why that is? No load on the engine.

At 55 in 5th gear I'm turning about 2200-2250 if I remember right. Hum,
thats about the same RPM as a 4:10 at 65mph.

Above 60 in 5th the 24V noise box is to loud inside the cabin. I know horsepower helps out a 3:55 alot. I recently put a programer for towing on my truck. The increase in power on the Stage 2 setting increase the hand calculated miles to 11.7 or there abouts on a trip from Suffolk Va to Melbourne Florida last week. The first day of the trip I averaged 9.0 mpg, hand calculated. Was towing into a 15-25mph SW wind all day. The extra HP helped as I would be down in the 7 mpg range otherwise.

I have a family member that has a 16,500lb Carri Lite, Carriage Fifth Wheel.
Its pulled by a 2005 Stock Dodge Cummins, six speed with 4:10's. Combo weight is just above recommended by Dodge. The combo recently did a 16,500 mile trip to Alaska from Florida and averaged 12.5mpg. If that had been a 3:55 it would have been much less.

He can get 19.5 mpg on the hwy just by reducing his speed on a 70mph hwy.
It seems the magic number for mileage is under 2000 rpm's.

blackdiesel

Your conparing a 2nd gen to a 3rd gen, I'm conparing two 02 3500's, one with 4:10's and one with 3:55's with the same mods. and my truck will out pull dads so bad, that if he has to pull very far he will get my truck.

CoastalDav

I see you commented on the 2005 truck and trailer as 3rd generation to 2nd generation. There was no comparsion meant. I think we are talking rear ratio.

If you have a way to monitor boost you'll see in 6th gear, a 3:55 rear pulling
10K will require more boost than the same truck with 4:10's. Everytime you hear that turbo, your under load and burning fuel.

There is no way a 3:55 will outpull at 4:10. It will in top end only not in weight.

Dave

blackdiesel

Thats wrong in nearly every aspect. The ONLY thing the lower gears are good for (4.10's) is to get a load rolling. and if its that heavy, put it in 4 low to get moving then shift back into 4hi or 2hi.

If you want to hear cab noise, go run a 4.10's in a second gen at 65 miles an hour. its night and day difference from 3.55's

And saying you wern't comparing a 3rd gen to 2nd gen is just like saying that a gas burner with 4.56's or lower would outpull a comprable diesel with 3.55's. The 3rd gens have more hp and tq out of the gate.

And, in case you didnt know, the boost is where your power is on a turbo charged diesel. So, when you tow, ideally you need boost built

If you travel below 50 mph at all times, yes 4.10's are for you. But if you want to pull at highway speeds so you dont get ran over by 40 ton trucks, you ought to opt for the higher gears.

Dissagree if you like, but Dad and I have been there, own that. And this is first hand experience

P.S. the extra 5 mpg i get over dad is a fat bonus

Fishin2Deep4U

I don't have any issues towing as much weight as I dare with 3.54s and 285 tires.

I think 4.10s would be nice with taller rubber. Or if I only towed very heavy all the time. But I like to be able to crank the boat down the freeway at the speed limit (70mph).

And since this is the PNW, we have mountains to go over. So, if I can do it with taller gears, I am sure others can as well. In my case, adding power has helped with every aspect of towing with taller gearing.

Dave

caper

Having both and driving them everyday the 4.10s are great around town but on the highway there a little low , my advice if your towing 10K or more all the time get 4.10s otherwise 3.55 will do.

CoastalDav

Originally Posted by Black Diesel

"If you want to hear cab noise, go run a 4.10's in a second gen at 65 miles an hour. its night and day difference from 3.55's"

I think I said that in my previous post.

"And, in case you didnt know, the boost is where your power is on a turbo charged diesel. So, when you tow, ideally you need boost built"

Maybe you missed the point here. When a Diesel is loaded like when your towing, your boost is up, let say 12psi, once you get the load moving and at speed. If your able to reduce the boost needed to maintain that speed, your saving fuel, reducing EGT's and it also means the engine is not loaded at much as it was before.

The 4:10 does exactly that compared to a 3:55 pulling the same weight. My boost runs around 9-12psi towing at 65mph in 6th. When I go back to fifth gear and run the same RPM the boost is down to 5-6psi. The gearing change has taken the load off the engine, just like the 4:10 does in 6th gear when towing as compared to the 3:55.

"If you travel below 50 mph at all times, yes 4.10's are for you. But if you want to pull at highway speeds so you dont get ran over by 40 ton trucks, you ought to opt for the higher gears."

The ideal engine speed for towing with a cummins engine is 2200-2300rpm. Cummins will tell you that and I'm sure if you search here you can find that. So, at 65mph with a 4:10 towing in 6th gear, the rpm's are right there. With the 3:55 your around 1800 rpm's and you'll find yourself downshifting unless your running 70mph+ to get the RPM's up in that range.

Also most trailer tires have a speed limitation of 65mph in writting when you buy them. Goodyear says their ST tires loose 10% rating above 65mph and it gets worse as you increase speed. So why would you want to tow faster than 65mph?

"Dissagree if you like, but Dad and I have been there, own that. And this is first hand experience"

I do.

"P.S. the extra 5 mpg i get over dad is a fat bonus"

You will never get 5mpg more, heavy towing, with a 3:55 than a 4:10. That may be true if your running the hwy at 75mph and not towing. Don't do that either. 68 is as fast as I run when unhooked. Above 2000rpm the fuel comsumption increases dramatically.

The next time I'm towing my fifth wheel, I will record (on the HyperPac) a run at 60mph in 6th gear, and one at 60mph in 5th gear. I think its possible to print that info from the HyperPac. It will show boost, manifold pressure, RPM,
Speed, Water Temp, and EGT (if I get the probe). I will send you a copy if you wish so you can see the load change.

My email address is MarServs@Aol.Com Feel free to contact me at any time.

Dave