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An explaination of the 2009 AWD system

25K views 7 replies 4 participants last post by  drag_racer 
#1 · (Edited)
3/30/2009 EDIT- Added Front Axle disconnect info, no Chrysler description for it yet, so I had to modify a 2000 Ram (BR/BE) desription to make things easy.

:modding:
For those of you who didn't realise or know yet, the Magna Steyr MS140 transfer case is gone. The new unit is the Borg Warner 44-40. It is an electronic unit. There is also now a front axle disconnect intergrated with the intermediate shaft that runs through the oil pan.Read about it:



DESCRIPTION

The Borg Warner 44-40 transfer case allows torque to be variably applied to the front axle. By allowing variable application of torque between the front and rear axles, this all-wheel drive system can be used on dry pavement without the typical torsional windup that will occur with a standard four wheel drive transfer case. The drive system of this transfer case consists of an input shaft and drive sprocket/clutch assembly, and an output shaft and driven sprocket. The drive and driven sprockets are connected by a drive chain. The clutch assembly consists of a pulse width modulated electromagnetic actuator and a multi-disc clutch pack, and allows variable application of torque to the front axle based on traction and driving conditions. The input shaft of the transfer case is connected to the rear propeller shaft, which drives the rear axle. The output shaft of the transfer case is connected to the front propeller shaft, which drives the front axle.

OPERATION

The Borg Warner 44-40 is a full time all-wheel drive transfer case with a fixed gear ratio. Depending on traction conditions, the Drive Train Control Module (DTCM) will modulate the electromagnetic clutch assembly to vary the amount of torque applied to the front axle. Torque is transmitted through the input shaft to the clutch and drive sprocket assembly, and is transferred directly to the rear propeller shaft, and to the output shaft and front propeller shaft by the drive chain. The oil pump circulates gear lube throughout the case to provide clutch cooling, and the DTCM monitors the temperature of the transfer case with a temperature sensor.

If you have EVIC, it can display wether you're in Rear Wheel Drive or All Wheel Drive.

From the 2009 Owners Manual:

This vehicle is equipped with an active on-demand All Wheel Drive (AWD) system which makes available optimum traction for a wide variety of road surface and driving conditions. The system minimizes wheel slip by automatically redirecting torque to the front and rear wheels as necessary.

To maximize fuel economy, your AWD vehicle automatically defaults to Rear Wheel Drive (RWD) when road and environmental conditions are such that wheel slip is unlikely to occur. When specific road and environmental conditions require increased levels of road traction, the vehicle automatically shifts into AWD mode. Automatic AWD operation could be activated by outside temperature, wheel slip, or other predetermined conditions (there may be a slight delay for AWD engagement after a wheel slip condition occurs). AWD can also be manually selected by moving the shift lever into Autostick mode (+/-) or activating the windshield wipers for an extended period of time.

Note: If the "t Case" or "Service AWD System" warning message appears after engine start up, or during driving, it means that the AWD system is not functioning properly and that service is required.

Front Axle Disconnect





DESCRIPTION


The front axle disconnect system consists of the following components:

-DTCM
-Front Axle Disconnect Module (Intergral to Transfer/Intermediate shaft)
-Drive Train Control Relay
-Related wiring

OPERATION

The Front Axle Disconnect Module (Solenoid) is controlled by the DTCM. The DTCM grounds the Drive Train Control relay, which provides Run/Start power to the Front Axle Disconnect Module. The DTCM controls the disconnect solenoid by grounding part of the solenoid, to switch from two wheel drive mode to all wheel drive mode, or vice versa. When the solenoid is grounded, the solenoid begins to move the shift fork and collar within the front axle intermediate shaft. In the all wheel drive mode, the shift collar connects the axle intermediate shaft to the axle shaft to supply engine power to both front wheels. In two wheel drive mode, the shift collar is disengaged from the intermediate shaft and the intermediate shaft is allowed to free-spin. When the two shafts are disengaged, the load on the engine is reduced, thereby providing better fuel economy and road handling. A position sensor is intergral to the disconnect module to report disconnect operation to the DTCM. The disconnect module also is constantly grounded.
 
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#2 ·
I have a 2009 SXT with awd. The awd is always on when it is below 39 degrees. I don't like the hit my gas mileage takes for this and am worried the awd will wear out--especially since it is controlled by pwm clutches. I would like to install a relay that would shunt the air temp sensor in the grille with a resistor and fool the sensor into thinking it is warmer outside. Is this possible and would it interfere with proper engine performance?
 
#3 ·
Is it known if the DTCM is at all compatible with the 05-08 electronics? IE: does it talk to the TCM at all and is the TCM from 05-08 the same as 09+? I'm looking at upgrading to a 6.1 based stroker in a couple years, and with that probably an aftermarket PCM to get rid of the drive-by-wire and go to cable throttle. With the added power, obviously the transfer case needs to be beefed up and the 09+ is supposedly a stronger design. It would also be nice if I can find a way to bypass the DTCM to force the transfer case to RWD mode so I can go into burnout contests.

Basically want to know if it is possible to upgrade to the Borg Warner case without finding a 09+ parts car and rewiring my whole car.
 
#5 · (Edited)
That's what I'm thinking. I don't want the OEM control (on when cold, on when tires slipping, etc.) I just want to be able to simply switch between AWD and RWD like a truck. Now whether that's possible or not that's something to be looked into. Even if it has to stay locked in AWD, if it's a stronger transfer case to start with that may be worth while looking into when a brand new transfer case with DTCM at most is about $1650 + shipping.

If it needs any sensor inputs, I wonder if you could emulate those if the DTCM is mandatory. Or just find the wires going to it that engage the AWD system, and simply run a switch inline to energize it thus turning AWD on and bypass the DTCM completely.
 
#7 · (Edited)
Maybe once I blow up the 05 case I'll buy all the parts for the Borg Warner case and see if I can make it work. Nothing is impossible, just might take a lot of work. It's probably really simple when you break it down.....DTCM receives the sensor readings to know how to adjust the torque ratio to the front and send power accordingly to the transfer case. If you can emulate that with a home-made module (since you shouldn't need a can-bus module due to not hooking it up to the OEM system unless I'm missing something), then you just need to figure out which wires need to receive power (and how much power) to activate the transfer case and put it into AWD mode with max torque split and not worrying about the variable torque split.
 
#8 ·
After reading the error codes for the DTCM on here: http://www.atraonline.com/gears/2009/2009-03/2009_3_38.pdf

It looks like the DTCM is tied to every module in the car. I'm thinking the only way to do it (aside for swapping everything from a 09+ car into your 05-08), may be a standalone controller, which after examining the wiring diagram doesn't seem overly difficult. You just need to figure out how much power is needed to send to each shift controller.
 
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