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An explanation of the 2009 AWD system

40K views 48 replies 20 participants last post by  Tbird100636 
#1 · (Edited)
An explanation of the 2009-Current AWD system

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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#44 ·
If I ever break the t/case, will the '09+ one bolt right up?
 
#45 · (Edited)
No early AWD systems are mechanical and always active. '09+ are electronic and somewhat selectable given the conditions given in this thread. And it was stated on the first page that a retrofit would probably include wiring, parts, and programming not impossible but pretty near.
 
#48 ·
Hi all,
After much fruitless searching through the forums, this seemed like the best place to post my question, given the excellent explanation of the AWD system...

Has anyone had experience with error code C147B - "Front Axle Disconnect Sensor Performance"?

I have a 2011 Charger R/T AWD, and the AWD system has been giving me some massive headaches over the past year or so. For quite some time, the system would (only sometimes) randomly decide to "lock" in either 2WD or AWD - whichever mode it happened to be in at the time - and give the "Serv AWD" light. Frustratingly, no error code would be stored, and neither my mechanic nor a local Dodge dealer could figure out what the issue was (despite being charged for 3 hrs of shop time at Dodge!! Ugh). Shutting the engine off and restarting it would typically clear the problem, at least for a little while. ... Now, fast-forward to today, and the AWD system works even less frequently - but at least has provided me with an error code!

I know there was an AWD-related recall having to do with a wiring harness that needed to be moved in order to prevent interference (or something like that), but it has been completed on my car - so that isn't it.

Any experience or thoughts on what the problem might be / what needs to be done to fix it would be greatly appreciated... I'm hoping it is as simple as replacing the disconnect sensor and wiring, but I'm all ears if anyone knows WTF is going on or what the root cause may be.

Thanks very much in advance!
 
#49 ·
Hello folks, bringing this back from the cellar to update that this AWD system is still in use to this day, on Chargers, 300s, and Challengers. It still uses the Borg-Warner 44-40 active transfer case, and a front axle disconnect integrated with the intermediate axle shaft.
 
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