2011 W/ 5 Speed or 2012 W/ 6 speed.
#1
10-21-2011, 06:42 PM
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2011 W/ 5 Speed or 2012 W/ 6 speed.
I am about to purchase a 3 Gen D and have looked over they quite a bit and have taken a few on test drives. Just would like to know if there is any improvement on fuel economy with the 2012 6-Speed transmission or is it the same as the 2011. Does anyone have the any actual calculation for the 2012 with the V-8?
#3
10-22-2011, 09:18 AM
I have about 3,000 miles on my 2012 V8 AWD Citadel. I just drove from NY to SC two days ago and averaged 19 mpg on the highway with the cruise control set at 65-70 mph. I drove through the night so traffic did not affect the mpg. That 19 mpg average was calculated by dividing the miles driven by gallons at fill-up. The best mpg the truck computed was 20.8 mpg.
Normally when I'm home and drive a mix of highway and around town I average about 16.8 mpg. I expected better mpg with the 6 spd, but when I got the real owners manual from Dodge I realized that the 6 spd is just a 5 spd that can be manually shifted into 6 different gears. If I go out to the truck later I will look to find the actual shift pattern when the truck is in Drive. I believe it skips either 3rd or 4th gear.
Normally when I'm home and drive a mix of highway and around town I average about 16.8 mpg. I expected better mpg with the 6 spd, but when I got the real owners manual from Dodge I realized that the 6 spd is just a 5 spd that can be manually shifted into 6 different gears. If I go out to the truck later I will look to find the actual shift pattern when the truck is in Drive. I believe it skips either 3rd or 4th gear.
#6
11-16-2011, 01:09 AM
As stated above the 6 speed is just a sneaky trick to make people think they are getting something better. They have the exact same gear ratios, same fuel econ...
Five speeds: the 545RFE transmission
In 2001, with programming changes and an extra, taller overdrive ratio, the 545RFE was born — still ignoring the “prime” or kickdown gear.
The 545RFE has a sophisticated design, despite having engineering that reaches back to the rock-solid Torqueflites.
Engineers decided that instead of having six forward gears, it made sense to program the transmission to act as a five-speed with an alternate second gear for downshifts. So, for instance, cruising a healthy highway speed of 70 miles per hour (110 km/h) on a 545RFE would yield a 2000 RPM, about 200 RPM less than the 45RFE programming, which means less fuel consumption.
During a recent live Q & A chat session with Washington Post automotive columnist Warren Brown, who has covered the car industry since 1982, I asked him about the importance of having the extra gear and whether it's a big selling point for buyers.
"The reason you have gears is to reduce engine stress -- strain, work -- at higher loads, increased speeds," Brown said. “Thus, 5-speeds are generally more efficient than four, six are more fuel-efficient than five and so on. You might note than German car companies are now rolling out seven-speed and eight-speed transmissions [Chrysler is moving to eight and nine speed automatics over the next two years.] Others are trying to do away with fixed gears altogether through the installation of gearless (no fixed gears), continuously variable transmissions (CVTs).”
As to the question of why the 545RFE has two overdrive gears that are so close to each other, engineer Bob Sheaves noted that size is an issue with planetary gears; most likely, the top 0.67:1 ratio gear was chosen because that was the largest one that could fit into the available space, without requiring changes to the design of the Jeeps and trucks using the transmission.
When towing (in some vehicles), a “Tow/Haul” mode provided crisper shifts to cut wear on the transmission, and reduced gear searching by holding lower gears longer. The system also selected lower gears when going downhill, to use the engine’s braking capability. In 2006, Chrysler claimed that the transmission had been “refined for higher-quality shifts;” it was strong enough to give the Jeep Commander and Grand Cherokee class-leading towing capacity of 7,200 lbs. The changes included a redesigned solenoid to provide quieter operation when shifting (ending “solenoid clatter”), and a turbine damper to cut noise and vibration from the torque converter.
Used in Chrysler's fleet of rear-wheel drive trucks, including the Jeep Liberty, Dodge Ram, Dodge Dakota, Dodge Durango and Jeep Commander over the past decade, the 545RFE is sophisticated, multi-ranged, and electronically controlled by a Transmission Control Module (TCM). Its shiny bellhousing -- a one-piece die-cast aluminum casing -- resembles a rocket ship designed by NASA engineers.
The 545RFE combines optimized gear ratios for responsive performance, including maintaining speed on long or high grades, without sacrificing efficiency at highway speeds; efficiency features including variable line pressure; and it has a low NVH (noise, vibration and harshness) thanks to ribs integrated into the case that increases multi-angular torsional rigidity.
The 545RFE is equipped with dual lubricant filters, including an internal main sump pan filter and an external canister-type pump return filter. The fluid capacity for service refill is 6.55 quarts (6.2 liters) and its fluid type is Mopar ATF +4. (Earlier units were specified as taking ATF+3 but ATF+4 is a superior fluid which can substitute for ATF+3).
Despite its steady improvement over the years, the 545RFE isn't without fault, and critics sometimes complain about its choice of gear ratios. While the 545RFE, as used in Ram trucks, may not perform as well as its Ford counterparts for unloaded acceleration, the 545RFE keeps running when the Ford runs out of reserve torque rise; it’s better suited for high loads and steep grades. The transmission is well suited for the large torque band of the Hemi V8, as well as previous engines it and its predecessors were used with. (The 545RFE has been used with numerous engines, including the 3.7 V6, 4.7 V8, 5.7 V8, and VM 2.8 diesel).
In 2009, modifications were made to the 545RFE that enabled drivers to select the highest gear the transmission would shift to, which has proved a helpful feature for towing, hill climbing, and hill descent.
With the 545RFE, Chrysler has equipped its trucks with a smooth and responsive rear-wheel transmission, one that requires few repairs. A six speed version is expected in 2012; in addition to using all gears in normal acceleration rather than reserving one for kickdown, some are speculating that it may have different ratios.
65RFE
The next six speed derived from the 545RFE was the 65RFE, initially used with V8 versions of the Ram 1500, Durango, and Grand Cherokee. The 65RFE does not have six forward gears in regular automatic mode, only in ERS/AutoStick mode; it is essentially a software and name change, which allows people to reach the “prime” gear via ERS rather than kickdown. An internal Chrysler communiqué to dealers summarized the change in a similar fashion.
Gear
545RFE
65RFE
1 3.00
2 1.67
3* 1.50
4 1.00
5 0.75
6 .067
Reverse 3.00**
* On 545RFE, 3rd is only accessible via kickdown in some situations, and is referred to as “2 prime.”
On 65RFE, 3rd is only accessible via kickdown in some situations and use of manual override.
** Chrysler specified a 2.21:1 reverse gear in some applications, including the Jeep Liberty diesel.
Five speeds: the 545RFE transmission
In 2001, with programming changes and an extra, taller overdrive ratio, the 545RFE was born — still ignoring the “prime” or kickdown gear.
The 545RFE has a sophisticated design, despite having engineering that reaches back to the rock-solid Torqueflites.
Engineers decided that instead of having six forward gears, it made sense to program the transmission to act as a five-speed with an alternate second gear for downshifts. So, for instance, cruising a healthy highway speed of 70 miles per hour (110 km/h) on a 545RFE would yield a 2000 RPM, about 200 RPM less than the 45RFE programming, which means less fuel consumption.
During a recent live Q & A chat session with Washington Post automotive columnist Warren Brown, who has covered the car industry since 1982, I asked him about the importance of having the extra gear and whether it's a big selling point for buyers.
"The reason you have gears is to reduce engine stress -- strain, work -- at higher loads, increased speeds," Brown said. “Thus, 5-speeds are generally more efficient than four, six are more fuel-efficient than five and so on. You might note than German car companies are now rolling out seven-speed and eight-speed transmissions [Chrysler is moving to eight and nine speed automatics over the next two years.] Others are trying to do away with fixed gears altogether through the installation of gearless (no fixed gears), continuously variable transmissions (CVTs).”
As to the question of why the 545RFE has two overdrive gears that are so close to each other, engineer Bob Sheaves noted that size is an issue with planetary gears; most likely, the top 0.67:1 ratio gear was chosen because that was the largest one that could fit into the available space, without requiring changes to the design of the Jeeps and trucks using the transmission.
When towing (in some vehicles), a “Tow/Haul” mode provided crisper shifts to cut wear on the transmission, and reduced gear searching by holding lower gears longer. The system also selected lower gears when going downhill, to use the engine’s braking capability. In 2006, Chrysler claimed that the transmission had been “refined for higher-quality shifts;” it was strong enough to give the Jeep Commander and Grand Cherokee class-leading towing capacity of 7,200 lbs. The changes included a redesigned solenoid to provide quieter operation when shifting (ending “solenoid clatter”), and a turbine damper to cut noise and vibration from the torque converter.
Used in Chrysler's fleet of rear-wheel drive trucks, including the Jeep Liberty, Dodge Ram, Dodge Dakota, Dodge Durango and Jeep Commander over the past decade, the 545RFE is sophisticated, multi-ranged, and electronically controlled by a Transmission Control Module (TCM). Its shiny bellhousing -- a one-piece die-cast aluminum casing -- resembles a rocket ship designed by NASA engineers.
The 545RFE combines optimized gear ratios for responsive performance, including maintaining speed on long or high grades, without sacrificing efficiency at highway speeds; efficiency features including variable line pressure; and it has a low NVH (noise, vibration and harshness) thanks to ribs integrated into the case that increases multi-angular torsional rigidity.
The 545RFE is equipped with dual lubricant filters, including an internal main sump pan filter and an external canister-type pump return filter. The fluid capacity for service refill is 6.55 quarts (6.2 liters) and its fluid type is Mopar ATF +4. (Earlier units were specified as taking ATF+3 but ATF+4 is a superior fluid which can substitute for ATF+3).
Despite its steady improvement over the years, the 545RFE isn't without fault, and critics sometimes complain about its choice of gear ratios. While the 545RFE, as used in Ram trucks, may not perform as well as its Ford counterparts for unloaded acceleration, the 545RFE keeps running when the Ford runs out of reserve torque rise; it’s better suited for high loads and steep grades. The transmission is well suited for the large torque band of the Hemi V8, as well as previous engines it and its predecessors were used with. (The 545RFE has been used with numerous engines, including the 3.7 V6, 4.7 V8, 5.7 V8, and VM 2.8 diesel).
In 2009, modifications were made to the 545RFE that enabled drivers to select the highest gear the transmission would shift to, which has proved a helpful feature for towing, hill climbing, and hill descent.
With the 545RFE, Chrysler has equipped its trucks with a smooth and responsive rear-wheel transmission, one that requires few repairs. A six speed version is expected in 2012; in addition to using all gears in normal acceleration rather than reserving one for kickdown, some are speculating that it may have different ratios.
65RFE
The next six speed derived from the 545RFE was the 65RFE, initially used with V8 versions of the Ram 1500, Durango, and Grand Cherokee. The 65RFE does not have six forward gears in regular automatic mode, only in ERS/AutoStick mode; it is essentially a software and name change, which allows people to reach the “prime” gear via ERS rather than kickdown. An internal Chrysler communiqué to dealers summarized the change in a similar fashion.
Gear
545RFE
65RFE
1 3.00
2 1.67
3* 1.50
4 1.00
5 0.75
6 .067
Reverse 3.00**
* On 545RFE, 3rd is only accessible via kickdown in some situations, and is referred to as “2 prime.”
On 65RFE, 3rd is only accessible via kickdown in some situations and use of manual override.
** Chrysler specified a 2.21:1 reverse gear in some applications, including the Jeep Liberty diesel.
#7
11-16-2011, 12:24 PM
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#10
11-17-2011, 05:48 PM
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I think there was some confusion with Dodge and the stickers. When I was searching the dealers sites for our vehicle, all of the Hemi/AWD versions said 16/22 or something. The sticker on the vehicle I bought (Hemi/AWD) says 13/18 or something like that. And that's much closer to what we are getting. The best I've seen is around 20mpg (but its only got 500 miles and I haven't done too much testing yet).