Jeep Patriot Forums banner
Cancel
Create thread New Garage Forums

Four wheel drive vehicles only

Jump to Latest
21 - 40 of 76 Posts
#21 ·
jgg204 said:
4WD and 4x4 are not the same. 4WD is a more intense version of ESC/Traction control b/c it uses a differential to transfer power to an axle that normally wouldn't have power in a solely 2WD vehicle. it's a technology that is relatively new (within the past 15 years or so). 4x4 has been around for many decades. when there was no ability to detect "slip" due to the technology not having been developed, 4x4 vehicles were 2WD in normal operation, but you could manually engage the 4x4 mode.

AWD is a technology that gives power to ALL WHEELS, ALL OF THE TIME. even though the power distribution is not equal, ALL wheels are spinning ALL of the time. on a 4WD vehicle, only the main wheels are spinning and the other set of wheels is activate when slip is detected.

does that help?
Click to expand...
So what would you call Jeeps' old Command -Trac? Selec-Trac? Qudara-Tac, etc.?
 
#22 ·
jgg204 said:
in the Jeep Patriot, you are not supposed to activate 4x4 lock mode when driving 80 mph on the highway...
Click to expand...
My manual plainly says you can engage the 4WD lock at any speed. No mention of 80 mph or any other speed. I'm not saying that anything happens, other than the light coming on, but you can indeed pull the lever.
 
#23 · (Edited)
Wooden Dog said:
So what would you call Jeeps' old Command -Trac? Selec-Trac? Qudara-Tac, etc.?
Click to expand...
Command-Trac II : Command-Trac II® supports the new MP 1522 two-speed, part-time four-wheel drive transfer case, featuring smooth operation, shift-on-the-fly capability, and improved NVH control compared to systems with mechanical linkage. 2WD High is the usual driving mode, with the front driveline disengaged from the transfer case and power directed to the rear wheels. Selecting 4WD Lock via the electronic, console-mounted switch locks the front and rear driveshafts together; the two then rotate at the same speed and provide a 50 front/50 rear torque split, providing better traction on slippery surfaces. This transfer case allows for 2WD, 4WD high-range and low-range as well as neutral. Selec-Trac II supports the new MP 3022 two-speed, full-time active “on-demand” four-wheel drive transfer case. When driving in 4WD Auto mode, the transfer case clutch pack detects wheel slip and applies increased or decreased torque between the front and rear axles based on real-time driving conditions, thus optimizing traction. Under the right conditions, the vehicle can be driven by just one wheel. For added capability when traversing steep grades, rough terrain, or extremely poor tractions surfaces, the transfer case includes a 4WD Low mode. Electronic shifting between 4WD Auto and 4WD is accomplished via a console-mounted switch. A 2WD mode is also provided for some markets. NO 4WD UNLESS 4WD-AUTO MODE IS ACTIVATED BY USER, JUST 2WD OR 4X4 LOCK MODE. AXLES ARE NOT CONNECTED DURING REGULAR DRIVING, THUS BY DEFINITION THIS IS NOT AWD

Selec-Trac II: Selec-Trac II supports the new MP 3022 two-speed, full-time active “on-demand” four-wheel drive transfer case. When driving in 4WD Auto mode, the transfer case clutch pack detects wheel slip and applies increased or decreased torque between the front and rear axles based on real-time driving conditions, thus optimizing traction. Under the right conditions, the vehicle can be driven by just one wheel. For added capability when traversing steep grades, rough terrain, or extremely poor tractions surfaces, the transfer case includes a 4WD Low mode. Electronic shifting between 4WD Auto and 4WD is accomplished via a console-mounted switch. A 2WD mode is also provided for some markets. THIS IS 4WD WITH A LOW MODE AND NO LOCK MODE

Quadra-Trac I: The brilliance of this 4WD system is it's simplicity. Quadra-Trac I operates in a high-range, all-time mode delivering optimum traction in virtually any driving situation with no driver input required. THIS IS 4WD

Quadra-Trac II: This active full-time system functions in all-wheel-drive until additional traction is needed, then reacts by electronically engaging the clutch pack to transfer up to 100% of the torque to either axle. This system also features 2.72:1 LOW-RANGE and NEUTRAL. THIS IS AWD SINCE BOTH AXLES ARE CONNECTED ALL OF THE TIME. NO USER INPUT OR COMPUTER INPUT IS REQUIRED TO SHARE POWER. HOWEVER IF SLIP IS DETECTED THEN THE COMPUTER RECEIVES INPUT AND REDIRECTS POWER AS APPROPRIATE

i hope this helps clear things up
 
#25 · (Edited)
Wooden Dog said:
Not really, I can read the Jeep website just as easily as anyone. Just seems to be a difference in semantics. Jeep's website itself calls them all 4X4 systems.
Click to expand...
all of those systems at one point during operation can have 4x4 operation, or in other words all 4 wheels spinning at once. this could be several minutes with a 4x4-lock mode, or could be an instantaneous activation in the case of 4WD.

this is why they are called "4x4 systems"

does that help? lol
 
#26 ·
why would someone need 4x4 at 80 mph? I'd think you're S.O.L. at that point and should have done some prior planning. Heck, even at 40 mph!
 
#27 ·
ilflyya said:
why would someone need 4x4 at 80 mph? I'd think you're S.O.L. at that point and should have done some prior planning. Heck, even at 40 mph!
Click to expand...
When a semi goes past you in a snow storm on the freeway or if you need to pass the snow plow in a blizzard. This is common in Minnesota while driving 50 MPH in 3 inches of heavy wet snow.
 
Save
Reply Quote Like Like
#28 ·
jgg204 said:
all of those systems at one point during operation can have 4x4 operation, or in other words all 4 wheels spinning at once. this could be several minutes with a 4x4-lock mode, or could be an instantaneous activation in the case of 4WD.

this is why they are called "4x4 systems"

does that help? lol
Click to expand...
It's just semantics. Jeep calls everything from Freedom Drive I all the way to Rock-Trac and everything in between "4X4 systems".
 
#29 ·
so 4x4 isn't useless at such a high speed? I'm talking from the standpoint of a Cherokee. I know in them, you shouldn't even be in 4x4 at high speeds. At least that is what I was always taught, I don't have the manual in front of me or anything. In my Cherokee I was able to get by semis and plows in snow without 4x4.

I know 4x4 (Patriot) was useless while driving through Nebraska back in Jan of '09 on I-80 while on black ice. We were all doing 20 mph :-(
 
#31 ·
Taken from a post on Jeepforum it might help to anwer some questions.

OPERATION

The all-wheel-drive system requires no driver input or control. Under most driving conditions, it is passive and power is transmitted to the front wheels alone. Unlike all-wheel drive systems that rely on pumps or viscous fluids to transfer torque, this system requires no front-to-rear slippage for activation. This allows the system to transfer torque solely in response to accelerator pedal position. If the driver is asking for a lot of power, the system immediately starts clamping the electronically controlled coupling (ECC), transferring a high percentage of power to the rear wheels. This avoids front wheel slippage, as power to propel the car is transmitted through all four tires. This mode of operation is called open-loop operation in that there is no feedback to affect the torque transfer.

A second, closed loop, operating mode uses feedback from the wheel-speed sensors to determine the appropriate torque transfer. When the front wheels slip, the All Wheel Drive (AWD) Control Module tells the ECC to start clamping, sending power to the rear wheels. Attempting the same aggressive launch described above with the front wheels on ice and the rear wheels on dry pavement, the ECC sends even more torque to the rear wheels to minimize slippage and launch the vehicle. Both modes are always active with the closed loop mode layered on top of open loop mode to increase torque to the rear wheels when needed to maintain traction in extreme cases.

Power to the rear wheels is modulated under the following conditions:

Slipping on ice while backing up will send a lot of power to the rear axle.

Loss of traction while traveling at freeway speeds, for example hydroplaning on a puddle of water, will send very little power to the rear wheels because the controller knows at those speeds a lot of power is not needed at the rear wheels.

A third condition, which is independent of the others, uses wheel speed differences to determine when the vehicle is turning in a tight circle. This condition, which is indicated by a large discrepancy in side-to-side wheel speeds, causes the electronic control module to reduce torque to the rear wheels to prevent binding in the driveline. The electronic control module is always checking for this condition as well.

A fourth condition that is unique to this system is to influence vehicle dynamics. Other systems limit AWD to aiding traction or providing off-road capability. The primary focus is on launching the vehicle or going off road at speeds up to about 25 mph (40 km/hr). Above that speed range, they use it to limit wheel slip for traction. On this system, additional ECM calibration controls torque to the rear wheels for improved handling in the 25-65 mph (40-105 km/hr) range. In this speed range, the system increases torque to the rear wheels during cornering with the throttle open to make the car turn more easily - make the handling more neutral. This is more readily accomplished with an electronically controlled system, than with viscous-coupling or gerotor systems that require some degree of front-to-rear slip to transfer torque to the rear wheels. Above 70 mph (113 km/hr), the control strategy provides minimal torque to the rear wheels under normal driving conditions to aid fuel economy.

The control module also interfaces with the Electronic Stability Program (ESP) and traction control systems. The interface allows the ESP system to use the ECC to help gain control of the vehicle. For this purpose, torque transmitted to the rear wheels by the ECC can be reduced. This system is not traction control. It only works on situations where front-to-rear traction varies, for instance, front wheels on ice, rear wheels on dry pavement or climbing steep grades. AWD does not aid side-to-side traction. ESP does that through brake intervention on this system.
Click to expand...
 
#32 ·
jgg204: You sound very sure of your opinion, but alas, common usage of the phrases are different. All one has to do is look at the marketing of different vehicles to see that especially the terms 4x4 and 4WD do not in fact have such well defined meanings when commonly used. (AWD tends to usually refer to an open center differential system, in my experience.) In fact, 4x4 and 4WD are normally interchangeable and in order to know in more detail what kind of four wheel drive system a vehicle has, you need to look at the specs or manual. If a sign post says "4x4 only", the normal assumption would be that the vehicle needs to provide power to all four wheels. If they further state that "AWD not allowed", that would in my opinion mean that a locking center differential is needed.

jgg204 said:
4x4 : drive train can be locked and all 4 wheels provide equal power. only for low speeds in this mode though
Click to expand...
According to your logic, if I understood correctly, only vehicles with 100% lockers on both axles may be called 4x4. Then how do you explain the factory mounted 4x4 emblems in many four wheel drive vehicles with open differentials at the axles? Take our very own Jeep Patriot as an example. (Unless, of course, you mean "all wheels provide equal power as long as all wheels have sufficient traction", in which case the Patriot would of course apply.)

Here is one explanation of the terms 4x4, 4WD and AWD: http://en.wikipedia.org/wiki/Four-wheel_drive I do not necessarily agree with all of it, but the article just goes to show that the different phrases are used fairly loosely, without any strict technical definition in mind.
 
Save
Reply Quote Like Like
#33 · (Edited)
Tony1911 said:
jgg204: You sound very sure of your opinion, but alas, common usage of the phrases are different. All one has to do is look at the marketing of different vehicles to see that especially the terms 4x4 and 4WD do not in fact have such well defined meanings when commonly used. (AWD tends to usually refer to an open center differential system, in my experience.) In fact, 4x4 and 4WD are normally interchangeable and in order to know in more detail what kind of four wheel drive system a vehicle has, you need to look at the specs or manual. If a sign post says "4x4 only", the normal assumption would be that the vehicle needs to provide power to all four wheels. If they further state that "AWD not allowed", that would in my opinion mean that a locking center differential is needed.



According to your logic, if I understood correctly, only vehicles with 100% lockers on both axles may be called 4x4. Then how do you explain the factory mounted 4x4 emblems in many four wheel drive vehicles with open differentials at the axles? Take our very own Jeep Patriot as an example. (Unless, of course, you mean "all wheels provide equal power as long as all wheels have sufficient traction", in which case the Patriot would of course apply.)

Here is one explanation of the terms 4x4, 4WD and AWD: http://en.wikipedia.org/wiki/Four-wheel_drive I do not necessarily agree with all of it, but the article just goes to show that the different phrases are used fairly loosely, without any strict technical definition in mind.
Click to expand...

i do want to note the differences between how manufacturers market their vehicles and what is the true definition of the different technologies. i wasn't trying to explain what the common misinterpretation is, i was trying to explain what the true definitions are.

the reason why the Jeep Patiot has the 4x4 badge is b/c it has the 4x4 capability which differentiates it from a regular 4WD. not many 4WD vehicles have the ability to lock the differential. there was a very limited production lot of Ford Escapes that could do that in the early years of production, but they scrapped it and just stuck with 4WD. to give the Jeep Patriot a 4WD badge would be undermining its capabilities. to give the Jeep Patriot the 4WD and the 4x4 badge would be overkill.

as i said before, 4WD is a form of 4x4 and falls under a "4x4 technology" type of system...an "instantaneous reactionary" form of conventional 4x4 technology. it gives the benefits of all 4 wheels spinning but it maximizes the fuel economy by only introducing 4x4 when needed on an instantaneous basis when slip is detected. as i mentioned, 4WD is a relative new technology when compared to 4x4. without the "control system loop" , 4WD would not have been possible.

this argument just keeps going around in circles because people point to examples showing the misinterpretation and using it as evidence that what i am saying is incorrect. i will admit that the industry doesn't help, but the properties of each technology cannot be argued.
 
#34 ·
I think the terms 4WD and 4X4 have been used interchangeably for many years. Old Jeep Wagoneers were called 4WD and they're not very recent.
I think we're just playing with words here.

"The first US four-wheel drive vehicle was built in 1911 by the Four-Wheel Drive auto company (FWD) of Wisconsin. FWD would later produce over 20,000 of its four-wheel drive Model B trucks for the British and American armies during World War I. It was not until "go-anywhere" vehicles were needed for the military that four-wheel drive found its place. The Jeep, originally developed by American Bantam but mass-produced by Willys and Ford, became the best-known four-wheel drive vehicle in the world during World War II. Willys (since 1950 owner of the Jeep name) introduced the CJ-2A in 1945 as the first full-production four-wheel drive passenger vehicle."
4WD is not a new term. Perhaps some are using it to describe the newer systems, but as I said 4WD and 4X4 have been used interchangeably for decades.
 
#35 ·
Wooden Dog said:
I think the terms 4WD and 4X4 have been used interchangeably for many years. Old Jeep Wagoneers were called 4WD and they're not very recent.
I think we're just playing with words here.

"The first US four-wheel drive vehicle was built in 1911 by the Four-Wheel Drive auto company (FWD) of Wisconsin. FWD would later produce over 20,000 of its four-wheel drive Model B trucks for the British and American armies during World War I. It was not until "go-anywhere" vehicles were needed for the military that four-wheel drive found its place. The Jeep, originally developed by American Bantam but mass-produced by Willys and Ford, became the best-known four-wheel drive vehicle in the world during World War II. Willys (since 1950 owner of the Jeep name) introduced the CJ-2A in 1945 as the first full-production four-wheel drive passenger vehicle."
4WD is not a new term. Perhaps some are using it to describe the newer systems, but as I said 4WD and 4X4 have been used interchangeably for decades.
Click to expand...
i agree with you in that they have been used in an interchangeable fashion, but my point is that when they interchange them it is in fact an incorrect labeling of a technology.

i understand your confusion, and i was confused until i did a lot of research on the topic a while back.
 
#36 ·
I'm not confused, mostly just amused.
I do wonder about something, however. One Jeep tech told me that you shouldn't use 4WD LOCK on dry pavement, as it would cause excess tire wear and drivetrain wear, due to all wheels being locked and spinning together. I know this is true in a system like Command-Trac, but I didn't think the Patriot locks everything together, , and I know you can drive Selec-Trac, and the other Jeep systems (aside for Rock-Trac) in 4W High on the road no matter whether it's wet or cslcik or dry.
 
#39 ·
Wooden Dog said:
I'm not confused, mostly just amused.
I do wonder about something, however. One Jeep tech told me that you shouldn't use 4WD LOCK on dry pavement, as it would cause excess tire wear and drivetrain wear, due to all wheels being locked and spinning together. I know this is true in a system like Command-Trac, but I didn't think the Patriot locks everything together, , and I know you can drive Selec-Trac, and the other Jeep systems (aside for Rock-Trac) in 4W High on the road no matter whether it's wet or cslcik or dry.
Click to expand...
4 wheel lock, disables the transfer case slippage point in any 4x4 system. Even my old Quadra-trac which can be driven anywhere on any surface in regular drive, can not be driven on dry pavement in 4-lock or 4 low.

Much different than the Patriot 4x4 lever that just engages the central magnetic clutch providing 50/50 front rear distribution.

I would love to have a Patriot with light weight version of the Quadra-trac transfer case but still have the option of it functioning with front wheel drive only for better fuel economy.
 
Save
Reply Quote Like Like
#40 ·
jgg204 said:
i do want to note the differences between how manufacturers market their vehicles and what is the true definition of the different technologies. i wasn't trying to explain what the common misinterpretation is, i was trying to explain what the true definitions are.
Click to expand...
And I was talking about the sign mentioned in the original post. :) Even if we accept your definitions as the correct ones, that does not matter to the issue at hand, since the people who wrote that sign most likely do not follow the same definitions.

(Personally, I would like a bit better source than "some dude called jgg204 said so on the Internet" before arguing against common usage of terms... Got some? Sources, that is?)
 
Save
Reply Quote Like Like
21 - 40 of 76 Posts
About this Discussion
75 Replies
15 Participants
Last post:
Medic311
Jeep Patriot Forums
posts
678K
members
55K
Since
2006
Join our community to discuss the Jeep Patriot & Jeep Compass. Find answers to all your Jeep Patriot technical questions.
Full Forum Listing
Explore Our Forums
Jeep Patriot General Discussion Engine and Drivetrain Newbie Check-In Suspension and Tires Electrical and Audio