2013 Dodge Ram pickup trucks - Powertrain: Engine, Transmission, Axles
The 2013 Ram 1500 achieved best in class gas mileage with both the V6 and V8 engines, thanks largely to the new “TorqueFlite 8” automatic transmission.
The V6 model leapfrogged Ford to get best in class gas mileage with higher performance; it now has 305 horsepower and 269 lb-ft of torque, major improvements over the old 3.7 V6. (The Hemi also got a five horsepower boost.) Gas mileage for the Ram 1500 V6 is rated at 18/25, while the best Ford mileage is 17/23; Chevrolet lags at 15/20.
The Ram 1500 diesel option uses a VM 3-liter diesel, also used on the 2014 Grand Cherokee, with the eight-speed automatic; it is a state of the art engine. A Cummins V6 was originally planned (no relation to the big straight-six).
|4x2||Pentastar V6||‘Next Gen’ 4.7 V8||Hemi V8|
|Horsepower||305 @ 6,400||310 @ 5,650||395 @ 5,600||240|
|Torque||269 @ 4,175||330 @ 39,50||407 @ 3950||420|
|Features||Twin-cam, E85||E85||Cylinder cutoff||(Many)|
|Towing (max)||3,450 lb||6,050||11,500 lb||11,500|
|Payload (max)||1,810 lb||1,717 lb||3,125 lb||3,125?|
|Gas mileage||18 / 25 (HFE); |
|8HP capacity, lb-ft||332 (450 Nm)||(6 speed only)||(n/a)||516 (700 Nm)||516|
In a new development, Ram is charging around $1,000 extra for the V6, over the base V8 engine. The substantially more expensive HEF version gets 1 mpg more in tests than the standard V6, and includes the three-part tonneau cover and many systems changes (the stop-start system, grill shutters, fluid pre-heating, adjustable suspension, lower front air dam, and others — details); it also gets numerous options as standard features.
TorqueFlite 8: ZF Eight-Speed Automatic Transmission
The main powertrain improvement was the eight speed automatic, based on our look at the Dodge Charger V6 with its five-speed and then with the eight-speed. It is the first eight-speed automatic to be used in a pickup truck. Just as the new transmission cut around two seconds off the Charger’s 0-60 times while adding several miles per gallon to its highway mileage, it helps the new Ram V6 to beat the 2012 model by three seconds, 0-60, while increasing gas mileage 20%.
The eight-speed does not just add gears; it dramatically increases the range from first to top gear, shifts much faster than the older automatics, and is reportedly lighter than the 65RFE transmission.
The eight-speed makes a stop-start system possible, and one is available on “select Ram 1500 models:” it automatically shuts the engine off when the truck comes to a complete stop, conserving fuel. The engine restarts instantly when the gas pedal is used. The feature can be shut off if desired, but has little impact on acceleration and a large impact on city-cycle driving.
The V6 will come only with the 8HP45 “Torqueflite 8” is the sole automatic. The Hemi will start the year with the 2012 six-speed automatic and later will transition to a higher-torque version of the eight-speed, the 8HP70, which has identical gear ratios; it will become available during the first three months of calendar year 2013.
Unlike the shifter for cars, which some critics have disliked, trucks with the eight-speed get a dash-mounted dial shifter, a style used on Class 6-8 heavy duty trucks. The class-exclusive shifter allows quick blind-shift transitions from Reverse to Drive when towing or navigating out of mud or snow; it is completely electronic, with no shift linkage, cutting maintenance and eliminating a common source of problems in older, well-worked trucks. Low gear is obtained by using the gear-change buttons on the steering wheel.
Both the 8HP45 and 8HP70 transmissions are fully electronic, and can change their shift maps to meet current conditions; Ram has over 40 shift maps for specific conditions to optimize shift quality and shift points. The software uses engine torque gradients, kick down, longitudinal and lateral acceleration, hill detection, friction detection, downshift detection, cruise control, stability control interaction, and temperature to determine shift points and methods.
|65RFE||3.00||1.67||1.50||1.00||0.75||0.67||3.00||2.33||410 lb-ft (540 Nm)|
|8HP||4.71||3.14||2.10||1.67||1.29||1.00||0.84||0.67||3.30||4.04||332 / 516 lb-ft (450/700 Nm)|
The 8HP has a much higher range than the 65RFE, which means you can get a good economy gear for efficient highway runs without sacrificing a low first gear for power and speed. Rather than comparing any particular gear ratio to Ford, Chevy, or Toyota, we suggest that you look at the range and the overall top gear ratio with one of the four axle ratios (listed later on this page).
Gear changes are nearly imperceptible due to the even spacing of gear ratios and the speed of shifting. The transmissions have four gear sets and five shift elements (multi-disc clutches and brakes); only two shift elements are open at any time (on both six and eight speeds). By minimizing the number of open shift elements, drag losses can be reduced.
The advanced Pentastar engine has dual overhead camshafts (DOHC), high torque over a broad rpm range, E85 capability, and best-in-class noise, vibration and harshness (NVH). The Pentastar won Ward’s 10 Best Engines award in its debut year of 2011 and repeated this honor in 2012.
The 60-degree aluminum block is made of die-cast T380 aluminum with cast iron bore liners. Six bolt main bearing caps contribute to an extremely rigid lower structure. Cast aluminum pistons are fitted to forged connecting rods; aluminum cylinder heads with dual overhead camshafts and four valves per cylinder include integral exhaust manifolds. The large intake ports are a “tumble” design. Despite the high (10.2:1) compression ratio, the Pentastar V-6 runs on regular 87 octane fuel (or E85).
For better fuel efficiency across a wide torque band, the engine includes variable-valve timing (VVT) with dual independent cam phasing. Nearly 90% of the engine’s peak torque is available from 1,800 to 6,400 rpm.
For 2013, due to the increased power, customers can opt for a V-6 engine with a 4x4 and in crew cab models.
Hemi V8 and Next Generation V8
The new Hemi has long delivered high fuel efficiency with its variable valve timing (VVT) and cylinder shut-off technology (MDS). The 2013 Ram 1500 will be the first vehicle to combine the new eight-speed automatic and the HEMI V-8 engine (late availability).
The 5.7-liter HEMI V-8 has best-in-class towing and payload (11,500 pounds and 3,125 pounds, respectively, with the Ram 1500 Tradesman Heavy Duty). Cylinder shut-off deactivates four cylinders when full V-8 power is not needed, increasing gas mileage by up to 20%; the system operates nearly-instantly between 1,000 and 3,000 rpm, and has been time-tested.
VVT technology improves fuel economy by first closing the intake valve (to increase pumping efficiency) and, later, by increasing the expansion process of the combustion event. This allows more energy to be transferred to the wheels instead of being lost out of the exhaust as heat. VVT also improves engine breathing, which improves engine efficiency and power.
Interactive Deceleration Fuel Shut Off (iDFSO) cuts fuel to the engine during deceleration, improving fuel economy in both city and highway driving. Midgrade gasoline (89 octane) is recommended; 87 octane regular is allowed.
The Next Generation V8, a 4.7 liter single-cam design with 16 valves and normally-open check-valve lash adjusters, returns for 2013 against all odds; it has horsepower similar to the V6, with more torque. The engine has a cast-iron block with aluminum-alloy heads, and a 9.8 compression ratio. We asked Ram’s Dave Sowers if the 4.7 would continue throughout 2013. He said:
We have a 4.7 at least for ’13. A large portion of our sales today are HEMI. We think with the Pentastar we’ll sell some more V6s, and the 4.7 is kind of the ‘tweener engine. It’s still an important part of the lineup. We can produce as many as we need. It’s not a production constraint. It’s more of demand I would say. People who are buying V8s, most people, particularly individual consumers are buying the HEMI. Great name, great seat-of-the-pants feel, great power, and very good fuel economy.
Today, the ’12 model year, the 4.7 and 5.7 have similar EPA fuel ratings. 20 MPG highway in a 4x2 configuration. They vary a little bit in the city. With the 8-speed, the HEMI will be hands down better than the 4.7 in both power, acceleration, capability and fuel economy.
Thermal Management System
Thermal management to cut transmission wear and raise efficiency
A segment exclusive on the 2013 Ram 1500 is a new thermal management system, designed to quickly raise the transmission fluid temperatures to cut parasitic losses and wear, improving fuel efficiency by 1.7%. It is enabled by an electronic thermostat which constantly monitors antifreeze temperature; once it’s hot enough, warm engine coolant is circulated through a thermal exchange unit which heats up the transmission fluid. In most vehicles, the transmission heats up independently of the engine. (The system also works for engine oil.)
Chrysler’s Dave Sowers said:
We get benefit from bringing both of them [oil and transmission fluid] up to operating temperature faster. The primary benefit comes in the transmission. In colder climates, you could drive a vehicle for hours in the winter and the transmission might never reach that 190° (F) for the most efficient operation. So what we do is use some of that hot engine coolant through the heat exchanger to bring it up to 190° as quickly as possible, and that gives us efficient operation very quickly.
This is a big leap forward in efficiency given most customers’ drive cycles and like I said, the fact that they might never get to that level of efficiency. We even use it with engine oil. You might think that once you start running the engine, the engine, the coolant and the oil are all the same temperature but that’s not true. We’re circulating coolant around where the combustion process happens to take all the heat out that we need to. What we’re going to do is heat the engine oil up to that – about 190° – as quickly as possible too. More benefit comes from the transmission than from the engine, but it helps in both cases.
Why do you say that more benefit comes from the transmission? Because the engine oil would’ve heated up eventually anyway. So we’re speeding up in the engine. In the transmission case we’re getting to where we might not have ever got in cold temperatures and low loads.
Adding to industry firsts in a pickup truck is the stop-start system, on “select 2013 Ram 1500 models.” This new system improves fuel economy by up to 3.3%, or around one mile per gallon (mpg), in the truck’s city drive cycle. It shuts the engine off when the truck comes to a complete stop. Amenities (radio, gauges, heating or air conditioning, etc.) continue to operate, making the operation transparent to the driver. The engine restarts automatically when the driver releases the brake, allowing seamless acceleration.
The system monitors brake pedal position and vehicle speed over time to determine appropriate engine shut off, preventing frequent on/off cycling in heavy stop-and-go traffic situations. The starter, alternator, and battery have been upgraded on trucks with this system; the high-durability starter (with 300,000 tested on/off cycles) is in a stronger case, with heavy-duty flywheel teeth and a more robust starter solenoid. The new battery is 800 amps, with Absorbed Glass Mat (AGM) technology, and the alternator capacity is 220 amps. (These upgrades only apply to trucks with the stop/start system; standard alternators are 160 and 180 amp, and the standard battery is a 730 CCA model).
If the battery’s charge is reduced, the truck will discontinue stop-start until the battery is recharged to an acceptable level. A system disable switch is on the dash.
Two transfer cases are available on the 2013 Ram 1500: the Borg Warner 44-45, a part- time four-wheel drive; and the Borg Warner 44-44, an on-demand four-wheel drive system. Both transfer cases are two-speed models (2.64:1 low gear) engaged with a dash-mounted rotary dial (column shifter) or buttons (TorqueFlite 8 rotary e-shifter). The on-demand system is only available with the Hemi engine.
The part-time transfer case provides three operating ranges, 2HI (two-wheel drive), 4HI (four-wheel drive) and 4LO (low-range reduction four-wheel drive), and a neutral position. Operating mode may be switched between 2HI and 4HI while the vehicle is in motion, but the transmission must be in neutral to engage 4LO.
The on-demand transfer case provides four operating ranges: auto, 2HI, 4HI and 4LO. The auto range engages two- or four-wheel drive depending on road conditions. 2HI, 4HI and 4LO function the same as in the part-time transfer case.
Driveshafts incorporate 1350 series universal joints, two-piece thrust washers with triple-lip seals and improved journal cross strength.
|Overall Top Gear Ratio||2.15||2.38||2.63||2.75|
Two final drive ratios, 3.21 and 3.55, are available on both the 2WD and 4WD models, reducing engine rpm throughout the operating range for better fuel economy. Two higher ratios are also available.
Four-wheel drive models of the 2013 Ram 1500 use a front axle designed for optional air suspension or standard torsional independent front suspension, incorporating half-shafts that drive front hubs. The axle also has a disconnect system that automatically disengages the axle when four-wheel drive mode is disengaged, for increased fuel economy.
The rear axle uses a new optional air suspension or multi-link mounting design to facilitate a coil- spring setup, with forward-facing shock absorber brackets. Four gear ratios are available: 3.21, 3.55, 3.92 and 4.10.
An optional helical-gear limited-slip rear axle is optional; it instantaneously divides torque between the rear wheels in proportion to the traction available to each wheel. The system is smooth when turning corners because it responds only to variations in traction.
Pulse Width Modulation (PWM)
Pulse-width modulation reduces parasitic electrical load and increases durability of fuel delivery and forward cooling fan. The fuel efficiency improvement is small (0.4%) but measurable over the trucks’ long lifespan.
Chrysler’s Dave Sowers explained the system:
Our fuel pumps historically have been created so that I can haul a long grade with wide-open throttle and provide enough fuel pressure and volume to maintain my speed the whole way up. Previously, we had two fuel lines to the engine compartment: one with pressure, and one where we return pressure. [With returnless fuel injection], We moved that fuel pressure regulator from the fuel realm to the fuel pump itself. But the fuel pump always still came on and ran at full speed and we just relieved the extra pressure right back into the tank. So that was returnless fuel.
Now what we’re doing is on-demand. We use pulse width management to do that, where we will only turn the pump on when we need it to generate the power. So we get two benefits of that: lower electrical load and longer fuel pump life because we’re not running it all the time. What we did in the past was the equivalent of turning your stereo onto 10 and covering your ears when it’s too loud. Now what we do is turn the volume down.
We also use pulse width for alternators. That’s been true for a long time; that’s not a new technology. But we’re using it for our cooling fans as well, so we don’t have to run them at full speed, we can run them at partial speed. [You’ve had two-speed fans for a while, haven’t you?] Yes, but we’d turn them on and turn them off. Now we can vary the speed with pulse width. [He could not answer how many steps they had for the fan.]
Powertrain Warranty: 5 Years / 100,000 Miles
The 2013 Ram 1500 is backed with a best-in-class 5-Year / 100,000-Mile Powertrain Limited Warranty which cost parts and labor for covered powertrain component (engine, transmission, and drive system) and free towing to the nearest Ram dealer, if necessary. The warranty is transferable to new owners. The standard 3-Year / 36,000-Mile Basic Limited Warranty provides bumper-to-bumper coverage for the Ram 1500.
TorqueFlite 8: the name
Ram’s Dave Sowers said:
I was part of the process [of coming up with the name] but I can’t point back to a single person. It was kind of a general agreement when it came up. We look back at TorqueFlite… the TorqueFlite name was a period of time when Chrysler was known for having bulletproof, efficient transmissions. That’s a notion that we all still held. So when the name came up in discussion, we all agreed. It sounded good. We did some research. We did some online research, and we did some customer research, and it does resonate that way. It speaks to high-quality transmissions and efficiency.
When TorqueFlite 8 was originally used, the number afterwards referred to the number of cylinders in the engine it was made into. Now we’re using it to designate the number of speeds in the transmission.
So we’re going to have 8-speed transmissions behind 6-cylinders like the Pentastar, and now we announced today we’ll have them behind 8-cylinders like the HEMI and the truck.
In 2014, will I still see the 65RFE? Yes.
For more information
- Pentastar V6
- 5.7 liter Hemi V8
- 65RE automatic transmissions
- ZF 8-Speed / TorqueFlite 8 automatic transmissions