Which axle ratio for 2013 Ram 3500 dually?

I am pulling 18,000 with 3.73's and a 4 speed on 33" tires and have no problems pulling hills and getting going. No I'm not stock but I am running around the same torque as the new trucks. If the roads are wet or heavily damp, I can break the tires loose if I'm not careful on take off. If it were me with the new trucks and only towing 18,000 I believe I would go with the 3.42 with the 6 speed trans.

goducks10 wrote:

4x4ord wrote:

Nautique200 wrote:
I have a 2012 with 3.73s and 35" tires. This is pretty close to the 3.42 ratio. I hate it. I have a hard time getting heavy loads moving, the truck has to turn a lot of RPMs to get the load moving. Also, the torque converter does not lock up on some of the steep mountain roads we haul our horse trailer (10K) up. These roads take 20 minutes of non stop climbing doing between 15 and 35 mph. The transmission just keeps building heat. On the highway, it does great. Everywhere else, it leaves me wishing I would have chosen the 4.10s so I would have been closer to a 3.73 final ratio.

I'm looking at getting a 2014 DRW Ram with the Aisin and Air Suspension. I will be getting 3.73s or 4.10s, I would never consider the 3.42.

Your 68rfe has a first gear ratio of 3.23:1
The Aisin has a first gear ratio of 3.74:1

In addition to the large difference in first gear ratios, I wouldn't be real surprised to hear the torque converter used behind the 800 lb ft Cummins with the 68rfe transmission was never really designed to handle all that torque.

So are hearing about 68rfe torque convertor failures?

No, not failures. The torque converter on the new Fords is extremely impressive. It was designed for a low stall speed, high torque input, a 1.9 times torque multiplication and low rpm (900 rpm) lock up. I am expecting now that Ram has turned over the responsibility of designing a transmission that can handle the 850 lbft torque of this Cummins to Aisin, the Aisin torque converter will be every bit as impressive as Ford's.

4x4ord wrote:

Nautique200 wrote:
I have a 2012 with 3.73s and 35" tires. This is pretty close to the 3.42 ratio. I hate it. I have a hard time getting heavy loads moving, the truck has to turn a lot of RPMs to get the load moving. Also, the torque converter does not lock up on some of the steep mountain roads we haul our horse trailer (10K) up. These roads take 20 minutes of non stop climbing doing between 15 and 35 mph. The transmission just keeps building heat. On the highway, it does great. Everywhere else, it leaves me wishing I would have chosen the 4.10s so I would have been closer to a 3.73 final ratio.

I'm looking at getting a 2014 DRW Ram with the Aisin and Air Suspension. I will be getting 3.73s or 4.10s, I would never consider the 3.42.

Your 68rfe has a first gear ratio of 3.23:1
The Aisin has a first gear ratio of 3.74:1

In addition to the large difference in first gear ratios, I wouldn't be real surprised to hear the torque converter used behind the 800 lb ft Cummins with the 68rfe transmission was never really designed to handle all that torque.

So are hearing about 68rfe torque convertor failures?

Nautique200 wrote:
I have a 2012 with 3.73s and 35" tires. This is pretty close to the 3.42 ratio. I hate it. I have a hard time getting heavy loads moving, the truck has to turn a lot of RPMs to get the load moving. Also, the torque converter does not lock up on some of the steep mountain roads we haul our horse trailer (10K) up. These roads take 20 minutes of non stop climbing doing between 15 and 35 mph. The transmission just keeps building heat. On the highway, it does great. Everywhere else, it leaves me wishing I would have chosen the 4.10s so I would have been closer to a 3.73 final ratio.

I'm looking at getting a 2014 DRW Ram with the Aisin and Air Suspension. I will be getting 3.73s or 4.10s, I would never consider the 3.42.

Your 68rfe has a first gear ratio of 3.23:1
The Aisin has a first gear ratio of 3.74:1

In addition to the large difference in first gear ratios, I wouldn't be real surprised to hear the torque converter used behind the 800 lb ft Cummins with the 68rfe transmission was never really designed to handle all that torque.

Nautique200 wrote:
I have a 2012 with 3.73s and 35" tires. This is pretty close to the 3.42 ratio. I hate it. I have a hard time getting heavy loads moving, the truck has to turn a lot of RPMs to get the load moving. Also, the torque converter does not lock up on some of the steep mountain roads we haul our horse trailer (10K) up. These roads take 20 minutes of non stop climbing doing between 15 and 35 mph. The transmission just keeps building heat. On the highway, it does great. Everywhere else, it leaves me wishing I would have chosen the 4.10s so I would have been closer to a 3.73 final ratio.

I'm looking at getting a 2014 DRW Ram with the Aisin and Air Suspension. I will be getting 3.73s or 4.10s, I would never consider the 3.42.

I am not doubting your post but I am very surprised by it because my Ford has 3.55 gears and 34" tires which makes it about 3.34 with 32" tires. It starts out with a 30,000 lb trailer as though there is nothing hooked to it. I attribute much of that to Ford's torque converter which can lock up at 900 rpm. My guess is that the Aisin set up will be much the same.

I have a 2012 with 3.73s and 35" tires. This is pretty close to the 3.42 ratio. I hate it. I have a hard time getting heavy loads moving, the truck has to turn a lot of RPMs to get the load moving. Also, the torque converter does not lock up on some of the steep mountain roads we haul our horse trailer (10K) up. These roads take 20 minutes of non stop climbing doing between 15 and 35 mph. The transmission just keeps building heat. On the highway, it does great. Everywhere else, it leaves me wishing I would have chosen the 4.10s so I would have been closer to a 3.73 final ratio.

I'm looking at getting a 2014 DRW Ram with the Aisin and Air Suspension. I will be getting 3.73s or 4.10s, I would never consider the 3.42.

Acei wrote:
So if there's almost no fuel penalty, why would anyone choose 3.73 over 4.10?

Not sure, but in like trucks 4X4 compared to 4X4 there really is not more then a 1-2 MPG difference. My 4X2 truck can hit 28 MPG routinely on the highway @ 65 MPH. Have a buddy that has the same truck but with 4WD and 4:10 gears with a gear vender overdrive unit and only sees 24 MPG driving the same area as me.

If you are looking at a 4X4 then I would think the 3:42 would be the right gear for your set up IMO. With the 4X4 if you need to back up a steep incline you can always switch the transfer case into low right? If going 2WD then I would diffidently look at a lower gear IMO.

Good luck and remember the cost to change gears later will be around 2K so it is cheaper to get them up front and will help resale also.

Don

Terry the torque management (on our older trucks) within the ECM looks at throttle position when starting from a dead stop. So if you want to launch off the line you are better off pressing only half way down and as soon as you hit 15 MPH you can go to WOT. Now that was what I was told by a power train engineer and that was back in 2006.

With all the newer vehicles now having to have stability/traction control, I'm not to sure what all it looks at now. The STC systems look at the wheel sensors along with some other inputs from other senors also. The TM was implemented to protect the drive train , transmission, torque converter, driveshaft/shafts and to a lessor extent the rear end/ends from WOT launches.

Don

So if there's almost no fuel penalty, why would anyone choose 3.73 over 4.10?

Previous Ram was a 5.9 48re with a 3:73. New truck 2012 6.7 68re with max tow ie. 4:10. I have pulled the same fiver over the same hills. Now this may only apply to the Ram which is the truck you are asking about. The 4:10 makes a very positive difference when pulling the hills/mountains etc. On the flats either will work. Put on the tow/haul mode, engage exhaust brake set the cruise and truck on down the road. Mine is a daily driver and no regrets about fuel useage.