Ram 3500 (6.4 Hemi)3.73 vs 4.10 with TC

Congrats on the soon to be new truck! :)

You will not regret the 4.10 at all!

Congratulations on your choice and persistence to determine what was logical.

Jim

SoCalDesertRider wrote:
The tow/haul feature is not an alternative to lower ratio axle gearing. It does help make better use of whatever axle ratio is in the truck though.

Many thanks SoCalDesertRider. I finally understand these topics. The Ram pre-sales materials and manual are very vague and this is something I have been puzzling about.

The choice of 3.73 vs 4.10 axle ratio was my very last decision when ordering the truck. I actually put a deposit on the truck order then asked the dealer to hold the order while I googled this topic. It sounds like I definitely made the correct decision to get the 4.10.

I followed the advice always better to get too much truck than not enough truck. Too much truck might cost some gas mileage (and probably not that much), but not enough truck can become a very expensive problem. Similar logic to why I ordered 4x4. I may never use it, but the one time you need it could save a big problem.

Thanks everyone for the info....It's good to hear from people who own this truck with a similar set up.

Two other things done on the Ram is it locks out sixth gear (double overdrive) and disables MDS.

There is no evidence that the Ram transmission uses higher hydraulic pressure. I've looked numerous times and can't find it.

SoCalDesertRider wrote:

bigfootford wrote:
The lower your gear ratio the harder it is on the transmission during initial take off. The heavier your load the harder it is on the bands and clutches. Couple this with a slight heavy foot and the transmission is not going to last. Heavy foot through gear shifts add to the wear and tear of the TC and the clutches.

Jim

I'm pretty sure you meant to say HIGHER ratio gearing (smaller number, aka 3.73) is harder on the transmission than lower gearing (aka 4.10). :)

Yep! hahahaha

Mij

Jim

bigfootford wrote:
The lower your gear ratio the harder it is on the transmission during initial take off. The heavier your load the harder it is on the bands and clutches. Couple this with a slight heavy foot and the transmission is not going to last. Heavy foot through gear shifts add to the wear and tear of the TC and the clutches.

Jim

I'm pretty sure you meant to say HIGHER ratio gearing (smaller number, aka 3.73) is harder on the transmission than lower gearing (aka 4.10). :)

bobbolotune wrote:

SoCalDesertRider wrote:
With the 3.55's I wasn't able to reach 2800+ rpm at speeds I could tow at, without going down to 2nd gear. The 4.56's put me right in the engine's sweet spot, at reasonable towing speeds, in 3rd gear, while also multiplying the engine's higher output.

The thing I can say about my Ram 3500 with 4:10 axle ratio with the truck camper loaded is that it seems to downshift only when really needed. The shift points seem good. It is only on an incline that it needs to downshift to maintain speed. I can't compare with 3.73 axle ratio since I have never experienced that but the 4:10 axle ratio seems good about maintaining the higher gear. When it downshifts it seems justified that it really needs extra power to go up an incline.

There is also tow haul mode, a button on the dash. I played with that. It seemed to just make the engine run at higher rpm. It caused the transmission shift points to be at higher rpm. That is similar to the effect of lower axle ratio, so I don't know how to compare tow haul mode to lower axle ratio (I suspect the answer may be that lower axle ratio increases torque where tow haul does not???). I decided that with the load I was carrying tow haul wasn't necessary with my 4:10 axle ratio. It increased rpm which I assume means worse gas mileage, where I had enough power without tow haul mode (if I was hauling a heavy 5th wheel rather than a lightweight truck camper that could change). So I left tow haul mode off. As to whether 3.73 axle ratio with tow haul mode on is an alternative to 4:10 axle ratio... that is an interesting question that I don't know the answer to.

I don't know specifically about the Dodge transmission. Generally speaking, what the tow/haul feature does on most auto transmissions is-

-Hold the tranny in each gear longer before upshifting, so the engine shifts into the next higher gear at a higher rpm.

-Downshift the tranny sooner when decelerating, which takes better advantage of engine/transmission braking to slow the vehicle on down grades or when using the brakes.

-Holds higher line pressures in the transmission's hydraulic system, which makes the gear clutches hold tighter, saving from burning clutches under heavy use.

-Uses different program parameters for control of the torque converter lockup, overdrive lockout and gear shifting, to prevent the tranny from 'hunting' between gears or repeditively locking/unlocking the converter.

The tow/haul feature is not an alternative to lower ratio axle gearing. It does help make better use of whatever axle ratio is in the truck though.

bigfootford wrote:
Nice write up!

Jim

Thanks Jim

SoCalDesertRider wrote:
With the 3.55's I wasn't able to reach 2800+ rpm at speeds I could tow at, without going down to 2nd gear. The 4.56's put me right in the engine's sweet spot, at reasonable towing speeds, in 3rd gear, while also multiplying the engine's higher output.

The thing I can say about my Ram 3500 with 4:10 axle ratio with the truck camper loaded is that it seems to downshift only when really needed. The shift points seem good. It is only on an incline that it needs to downshift to maintain speed. I can't compare with 3.73 axle ratio since I have never experienced that but the 4:10 axle ratio seems good about maintaining the higher gear. When it downshifts it seems justified that it really needs extra power to go up an incline.

There is also tow haul mode, a button on the dash. I played with that. It seemed to just make the engine run at higher rpm. It caused the transmission shift points to be at higher rpm. That is similar to the effect of lower axle ratio, so I don't know how to compare tow haul mode to lower axle ratio (I suspect the answer may be that lower axle ratio increases torque where tow haul does not???). I decided that with the load I was carrying tow haul wasn't necessary with my 4:10 axle ratio. It increased rpm which I assume means worse gas mileage, where I had enough power without tow haul mode (if I was hauling a heavy 5th wheel rather than a lightweight truck camper that could change). So I left tow haul mode off. As to whether 3.73 axle ratio with tow haul mode on is an alternative to 4:10 axle ratio... that is an interesting question that I don't know the answer to.