i have a base 2008 sport 5speed, and i am wondering b4 4x4 is enguaged is the patriot FWD or constant allwheel drive? i do have the t- handle that just says 4x4 LOCK i dont have any special doo dads do i?


thanks '

chris

Chris - this has been answered many times in the forum. You can find great information if you do searches or look through different threads.

The Patriot makes 4x4 very easy. It is -always- in All wheel drive.

The Lock mode should only be used in Wet/Snow/Ice/Sand/Mud conditions. It locks the front/rear wheels at an equal power ratio 50/50 so that you get more traction. If you use Lock in dry conditions, you end up stressing the drive train because the wheels cannot spin easily.

It maybe better to explain that the FD1 4wheel drive system is more like an always ready system, not true all wheel drive. When in normal driving conditions, your patriot will be in front wheel drive, and the ESP system will be constantly monitoring your Jeep, if the need arises the ESP and roll mitigation system will activate and transfer power to the wheels as needed. As stated above the Lock mode should only be used in Wet/Snow/Ice/Sand/Mud conditions, using it in other conditions will just result in additional wear and tear or possible damage to your Jeep

so i was reading on the net, the FD1 is what i have correct? and with the 4x4 lock i can handle deeper snow and mud correct

Full time AWD,
no its FWD with 4x4 when engaged,
No it AWD with 4x4,

Last i checked it runs on 2 wheels, FWD
when lever engaged engages 4x4,
FDII has lower gear ratios to enhance the 4x4 capabilities, among other goodies

Watch this short, but insightful video. It explains both of the available Jeep Patriot 4x4 systems (FDI and FDII):



Jeep Patriot 4x4 Systems (FDI and FDII) (http://www.telusplanet.net/~homac/JeepPatriotFDI-FDII.wmv)



.

The video says that both of them are FWD in dry conditions to reduce friction and increase fuel economy. But I don't see how friction is reduced unless there are what amount to electric couplings at both of the rear wheels. Otherwise, in dry conditions the rear wheels will turn the rear axles, which will turn the rear differential, which will turn the rear driveshaft. The fact that the electric coupling disconnects the rear driveshaft from the engine will avoid drivetrain stresses on dry pavement, but I don't understand how it will reduce overall friction and fuel consumption.

Am I missing something?

It maybe better to explain that the FD1 4wheel drive system is more like an always ready system, not true all wheel drive. When in normal driving conditions, your patriot will be in front wheel drive, and the ESP system will be constantly monitoring your Jeep, if the need arises the ESP and roll mitigation system will activate and transfer power to the wheels as needed. As stated above the Lock mode should only be used in Wet/Snow/Ice/Sand/Mud conditions, using it in other conditions will just result in additional wear and tear or possible damage to your Jeep

when the fd1 senses slip and goes from fwd to 4x4, does that "4x4" light on the dash come on (or is this only lit with 4x4 lock)? is this what lets you know or is it just seamless and there is no indication ?

when the fd1 senses slip and goes from fwd to 4x4, does that "4x4" light on the dash come on (or is this only lit with 4x4 lock)? is this what lets you know or is it just seamless and there is no indication ?

The dash light only comes on in LOCK mode.

Here is the technical explaination from the Service Manual of how the system really works:

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.

The fact that the electric coupling disconnects the rear driveshaft from the engine will avoid drivetrain stresses on dry pavement, but I don't understand how it will reduce overall friction and fuel consumption.



Let's go to the extreme. If all 4 wheels by some chance happend to be completely different sizes (even minimally), they would turn at differing speeds while driving. We also have to differentiate between driven (from the engine) vs spining (cause by tires contacting the pavement)

With two wheels engaged, the differential can some what accomodate for this. It has to, when you go around a corner the outer wheel spins faster than the inner wheel.

Now to the extreme case where they are differing sizes with the front being bigger than the backs. It would try to make the car pull itself against something that doesn't want to move. Since it is the front tires "moving faster" than the rear, something has to give so increased friction. On dry pavement, it will usually be drivetrain and tire wear, in mud, the mud just flys a little more.

On a car with all wheels the same size, plain driving has different wheel rotations, mainly in turns. In general, the outer rotates faster than the inners, the fronts faster than the backs (the backs take a smaller radius, unless of course you have 100% all wheel steering) After a few thousand miles the tires will wear differently thus becoming differing sizes. This is why if you replace a tire, you might want to do them all at the same time and why tire rotation is such a big deal on a AWD vehicle.

I have to say, while testing the Patriot, the AWD is much better than my wifes Chevy Equinox. When that thing engages on the pavement, it sounds like it is going to rattle apart. If I remember right this is due to the fact that the fronts are driven 1% faster to add stability in slick conditions.

To the drive train spinning when not in "use". This is one reason why the 4x2 gets better gas mileage. The other would be the increased weight of the 4x4 system. It is back to when you had to get out an lock the hubs on your old 4x4. Two reasons there, save gas and save wear. With the newer CV joins, better lubrication and tigher tolerances, wear is not as much of a factor, but it still takes evergy to spin this stuff.

As a note:
AWD (All Wheel Drive) is an automatic thing. It may be that power is give to all wheels all the time through a viscous coupling to account for the differing rotation speeds. Or it is an on demand thing that engages a clutch, tourque converter, magic, ... to engage the other wheels when slip is sensed.

4x4 In most case means "manual" engagement and all four wheels are turned at the same RPM

Between the video and the last two posts from Gramps and tumprgt I think we have it covered. The service manual is quite clear.

In "real world" conditions I can say it works great in AWD mode and 4x4 lock mode. It works well in conjuction with ESP too.

Other than keeping control and not being able to spin the wheels easily you may see the ESP icon flash on your dash (looks like a car with two snakes following it). I have seen this when trying to accelerate on ice.


http://www.jeeppatriot.com/forum/attachment.php?attachmentid=1462&stc=1&d=1201370342



.

so i should not drive around in 4x4 lock mode??

so i should not drive around in 4x4 lock mode??


When you say "drive around" I am assuming you mean around town.

If you drive around town in 4x4 Lock mode you will find the following:


Reduced fuel economy
Excellent traction at low speeds (below 30km/hr)
Very slight increased wear on the drivetrain
Slight increase in tire wear


If you drive on the street in 4x4 mode every time your speed drops below 30km the system will distribute the power 50% front / 50% rear. This is great for traction, but in good conditions makes no sense, front wheel drive is fine.


.

If you are on Wet/Snow/Ice/Mud/Sand, you can keep 4x4 lock engaged.

The purpose is to get moving and then turn it off, but if you are going to maintain less than 15mph or continue to start and stop, you can leave it on.

Freedom drive I
http://www.jeep.com/en/4x4/how_systems_work/freedom_drive/


Freedom drive II
http://www.jeep.com/en/4x4/how_systems_work/freedom_drive_2/

Hi,

For my understanding, I can always activate the off-road mode even in dry condition,
the computer will switch it off above 25 mph.
This will not damage Patriot (it may not save fuel), right?

Hi,

For my understanding, I can always activate the off-road mode even in dry condition,
the computer will switch it off above 25 mph.
This will not damage Patriot (it may not save fuel), right?

There is so much confusion on this because the Patriot has so many various setups.
From your statement above, I believe that you have an FDII Patriot, and that you are asking that if you put your Patriot in "L" with the T-bar in the "LOCK" mode, that after 25MPH does the system disengage the LOCK?
If so I can tell you that the CVT2L provides an overall first gear ratio of 19:1 for crawling over large obstacles until the vehicle approaches a speed of 10 mph or more, after the 10mph the electronically controlled coupling ratios up to maintain speed and at speeds above 25 mph, the coupling delivers the same amount of torque to the rear axle as in the normal mode.

So it does not disengage the lock, this is why the Light stays on and if you drive in dry or normal conditions with the 4wheel drive LOCKed you are risking damage to you vehicle

Hi CJs07RIOT;

Thanks, mine is FDI, sorry about that.
My question is:
I always activate the off-road mode even in dry condition (in winter).
Will this damage Patriot?

The FD I doesn't have Off-Road mode, only a lock for the 4x4 coupler. Why do you feel the need to lock in the 4x4 mode in dry weather? I have lots of snow and ice during the winter and mine is engaged most of the time and not engaged when the conditions are rather nice. It really depends on the driving conditions. Are yours similar tio mine?

I've also heard that in the UK the lock is always on with no adverse effects.

Hi CJs07RIOT;

Thanks, mine is FDI, sorry about that.
My question is:
I always activate the off-road mode even in dry condition (in winter).
Will this damage Patriot?

No problem, since its FD1 you should have no problem driving your Patriot with the LOCK engaged for anything up to 50mph, but only when you encounter snow, ice, mud, or rain on a road with very very little grip

The potential issue is Axle/Transmission Windup this an issue that all parttime 4wheel drive vehicles face and I've tried to describe it below. The short of it is you should leave it out of LOCK unless your in the described conditions, the ESP program in the Patriot will be more than good enough in most normal conditions.


When a 4WD is traveling in a straight line all four wheels rotate at the same speed, but during cornering each wheel travels at a different speed due to the radius of the turn. When a part-time 4WD is in 4WD and it attempts to corner all wheels need to rotate at different speeds, but they cannot.

This creates the phenomena called "axle windup" or "transmission windup". High strain is placed on the drive shafts and transmission, eventually causing one of two things to happen. Either one of the wheels slips or spins to overcome the stress or the drive-shaft/transmission breaks. This is why part time 4WD’s should never select 4WD on tarmac or a surface with good grip. .

The FD I doesn't have Off-Road mode, only a lock for the 4x4 coupler. Why do you feel the need to lock in the 4x4 mode in dry weather? I have lots of snow and ice during the winter and mine is engaged most of the time and not engaged when the conditions are rather nice. It really depends on the driving conditions. Are yours similar tio mine?

I've also heard that in the UK the lock is always on with no adverse effects.

I guess I'm OLD school 4wheel drive
Gramps, do you know if the Patriot would actually experence Axle/Transmission Windup/Bind as I discribed above. Still trying to figure out this "electronic 4wheel drive"

IMO, there's absolutely no point to pulling the 4X4 lock on the road. Without it on, the Pat is going to put power to the back wheels when you need it, and it won't when you don't need it.

why would anyone want to reduce thier fuel economy by locking it on the road? It's not going to help you stop if you hit ice. If you loose front wheel traction, it'll put power to the rear wheels.

I guess I'm OLD school 4wheel drive
Gramps, do you know if the Patriot would actually experence Axle/Transmission Windup/Bind as I discribed above. Still trying to figure out this "electronic 4wheel drive"

I'm still taking it all in too. I'm trying to see what I posted back on post # 11 tells us anything about that. With it being an On Demand AWD I don't believe that it gets the windup/bind that other systems do. Those conditions are usually associated with the gear drive type 4WD systems and not AWD. The brake system has a lot to do with it too by slowing down the faster wheel as needed. I'll look for more info.

IMO, there's absolutely no point to pulling the 4X4 lock on the road. Without it on, the Pat is going to put power to the back wheels when you need it, and it won't when you don't need it.

why would anyone want to reduce thier fuel economy by locking it on the road? It's not going to help you stop if you hit ice. If you loose front wheel traction, it'll put power to the rear wheels.

I use mine because I am constantly stopping, turning off and getting behind slow drivers where the low speed traction on ice and snow is beneficial when starting out again. I rarely get up to 50 mph during my winter drives and when I do it's turned off. It's a lot more stop, start, slow down and turn than it is maintaining a constant speed. Constantly pulling the lever for on/off isn't really necessary, we're not talking about huge amount of gas consumed or extreme wear and tear on the tires or drivetrain. ESP is also a big factor and the 4wheel lock is icing on the cake at low speeds.

I guess I'm OLD school 4wheel drive
Gramps, do you know if the Patriot would actually experence Axle/Transmission Windup/Bind as I discribed above. Still trying to figure out this "electronic 4wheel drive"

The Jeep MK’s use a clutch pack coupling which functions like 2wd when the clutch pack not engaged, and like an On Demand 4wd system when the clutch is engaged by the computer or locked by manual control. Some other vehicles in this category have varying degrees of control in the torque distribution between front and rear via allowing some of the clutches in a clutch pack to engage and slip varying amounts.

AWD can be used on dry pavement because it employs the use of a center differential, which allows each tire to receive different amounts of power. This eliminates driveline binding, wheel hop and other driveline issues associated with the use of 4WD on dry pavement.

The Jeep MK’s use a clutch pack coupling which functions like 2wd when the clutch pack not engaged, and like an On Demand 4wd system when the clutch is engaged by the computer or locked by manual control. Some other vehicles in this category have varying degrees of control in the torque distribution between front and rear via allowing some of the clutches in a clutch pack to engage and slip varying amounts.

AWD can be used on dry pavement because it employs the use of a center differential, which allows each tire to receive different amounts of power. This eliminates driveline binding, wheel hop and other driveline issues associated with the use of 4WD on dry pavement.

Thanks, I was thinking that it had to use a center differential, but wasn't sure

I am from Barcelona and i not speak english very good. I speak Spanish. Sorry.
Tengo un Patriot con el sistema de traccion FDI y tengo una duda, sabeis si se le puede acoplar o instalar el FDII en un vehiculo europeo. Aqui en Espa?a solo se comercializa el motor 2.0 Diesel CRD. Gracias.
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I am from Barcelona and i not speak english very good. I speak Spanish. Sorry.
Tengo un Patriot con el sistema de traccion FDI y tengo una duda, sabeis si se le puede acoplar o instalar el FDII en un vehiculo europeo. Aqui en España solo se comercializa el motor 2.0 Diesel CRD. Gracias.

as of right now, no. but who knows that the future holds.

The Patriot's AWD system is an intelligent/predictive/intuitive on-demand AWD system.

Very few manufacturers (ie. Subaru, Audi, Mitsubishi) make AWD systems that operate, under normal driving conditions, in a full-time front-rear torque split. I believe that the Patriot's AWD system, functionally at least, is lumped in with that of the CRV, the latest generation Rav4, Escape, Rogue, etc.

I hazard to say that the term "4x4 Lock" is a huge misnomer. My interpretation of the "lock" is that it is more of a "bias".

Also, there was a previous comment about different tire diameters. I re-iterate the importance of tire rotation. If one tire is significantly smaller than the others it will spin faster and the AWD system may interpret that as a slip and engage the torque transfer system, full-time. This also means that, generally, you cannot replace just one or two tires. It is usually all four wheels at the same time.

Thank you for your answers, we will wait and see what happens.
Greetings from Barcelona.
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Well here's my 2 cent explanation. The 4x4 patriots are all fwd. In the event that the computer senses wheel slippage it will automaticly send power to the non slipping wheels. The 4wd lock mode is only for offroading, deep snow, mud , sand and so on. For most winter driving 4wd lock mode is not needed and driving around with it always on when its not needed is not a good thing. So I would only use the 4wd lock mode for snow deeper than say 4 to 6 inches or driving on the beach or driving offroad say to your favorite hunting spot. My guess is for those with the FDII system it works the same as the FDI system exept that the FDII system has a lower gear range for offroading and some additional things. Hope this helps.

Ok I listened to the video and the guy says how it works by automatically transfering power, but he says, best of all there is no driver input thanks to the cvt transmission.....so my question is what about the manual, does the system still transfer power to whatever wheels need it? or is it just fwd, then if u need 4x4 you have to lock it? I just found it kind of weird that he says thanks to the cvt transmission and just wanted to know if it still works with the manual transmission.

CVT is really only the transmission. the 4x4 system is all by itself and works the same for the Manual with FDI.