Another confusing thing: the specs for the TRX show different torque splits for different settings (Sand, Mud, Rock, Baja, Snow, etc.). How do they do that with a clutch pack? What would be the criteria? Slippage is easy...the computer knows the wheel speeds, engine speed, gear, steering wheel angle, lateral and longitudinal forces. How does it know torque split? How does it control it?
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Very Confused About Transfer Cases
- Thread starter DavidNJ
- Start date
Now I am confused. I have a Borg Warner 48 12 transfer case. I just drove it in 4WD high on bone dry asphalt and it only bucked and jerked a little and then only when the wheel was at the turn stop. Normal turns created a little extra rolling resistance but not a lot. Like I mentioned before, I could drive this thing in 4WD High on suburban roads and not even notice it, very different than the two other 4WDs that I've had. Something in the engineering has changed, for the better.
TNRamGuy
Ram Guru
Totally lost me
That is interesting since the question is whether the 48-12 uses clutches or a sliding dog ring to engage the front wheels. The 44-45 seems to use the sliding dog ring, or at least the part diagram shows that.
On the models with 4Auto there is a clutch back that has pwm signal to put pressure on the clutch plates controlled using the amount of slip between front and rear. The gear to drive the chain driving the front wheels is on the outside of the clutches, the input shaft on the inside.
The question is how much abuse the clutch pack can take. Both the TRX and 392 Rubicon (and I'm pretty sure the Raptors) have an auto mode using clutch packs. Magna has a brochure sheet online (link above in one of the posts) that shows a model with much higher torque capacity in both the clutch pack and in the planetary gear set that gives the 2.72 low gear (with 6 internal gears instead of 3).
There are a few earlier threads where people complain about the 4Lo and 4Hi not being there all the time after being set. And there are posts here and on transmission maintenance sites about the transfer cases with clutches overheating when snow plowing or on heavy sand.
The design with the clutch packs appears to be common including high power/high torque configurations (TRX, Raptor, 392 Rubicon). Is there really a problem? Of course, it is hard to test with Brake Locking Differential which confuses the issue. On Wrangler Rubicon reviews, reviewers have said the BLD worked well enough they never engaged the locking front and rear differentials, which was always one of the big Rubicon features. Purpose build off-road differentials had electric or air lockers in the rear and electric, air, or Detroit Locker differentials in the front.
This stuff isn't clear. The very limited info from Ram, Stellantis, and Borg Warner doesn't make it easier.
This fellow explains it better than me:
He is saying the systems with 4Auto and therefore a clutch pack fully or partially release the clutch pack pressure when the wheels turn or the throttle is released. If you are moving slowly over a slippery surface with minimal and intermittent throttle and turning of the front wheels to snake around stuff the 4Hi and 4Lo will unlock. On a slippery surface (rocks, mud going uphill, etc.) initial throttle application is with the fronts unlocked.
He is saying the systems with 4Auto and therefore a clutch pack fully or partially release the clutch pack pressure when the wheels turn or the throttle is released. If you are moving slowly over a slippery surface with minimal and intermittent throttle and turning of the front wheels to snake around stuff the 4Hi and 4Lo will unlock. On a slippery surface (rocks, mud going uphill, etc.) initial throttle application is with the fronts unlocked.
Thanks. It appears there is a Partial Off and Full Off mode. Maybe the complaints were from people who didn't have their trucks configured as they thought they were. It is unclear if BLD is off in Full Off or not. It says "BLD may remain enabled even if TCS and Electronic Stability Control (ESC) are in reduced modes."
ESC Operating Modes
Depending upon model and mode of operation, the ESC system may have multiple operating modes.
ESC On
This is the normal operating mode for the ESC. Whenever the vehicle is started, the ESC system will be in this mode. This mode should be used for most driving conditions. Alternate ESC modes should only be used for specific reasons as noted in the following paragraphs.
Partial Off
This mode may be useful if the vehicle becomes stuck. This mode may modify TCS and ESC thresholds for activation, which allows for more wheel spin than normally allowed.
To enter the “Partial Off” mode, momentarily push the ESC OFF button and the ESC OFF Indicator Light will illuminate. To turn the ESC on again, momentarily push the ESC OFF button and the ESC OFF Indicator Light will turn off.
NOTE:
For vehicles with multiple partial ESC modes, the push and release of the button will toggle the ESC modes. Multiple attempts may be required to return to “ESC On”.
Full Off — If Equipped
This mode is intended for off-highway or off-road use only and should not be used on any public roadways.
In this mode, TCS and ESC features are turned off. To enter the “Full Off” mode, push and hold the ESC OFF button for five seconds while the vehicle is stopped with the engine running. After five seconds, a chime will sound, the ESC OFF Indicator Light will illuminate, and the “ESC OFF” message will display in the instrument cluster. To turn ESC on again, momentarily push the ESC OFF button.
NOTE:
System may switch from ESC “Full Off” to “Partial Off” mode when the vehicle exceeds a predetermined speed. When the vehicle speed slows below the predetermined speed the system will return to ESC “Full Off”.
ESC modes may also be affected by drive modes (if equipped).
WARNING!
When in “Partial Off” mode, the TCS functionality of ESC (except for the limited-slip feature described in the TCS section) has been disabled and the ESC OFF Indicator Light will be illuminated. When in “Partial Off” mode, the engine power reduction feature of TCS is disabled, and the enhanced vehicle stability offered by the ESC system is reduced.
Trailer Sway Control (TSC) is disabled when the ESC system is in the “Partial Off” mode.
WARNING!
In the ESC “Full Off” mode, the engine torque reduction and stability features are disabled. Therefore, enhanced vehicle stability offered by the ESC system is unavailable. In an emergency evasive maneuver, the ESC system will not engage to assist in maintaining stability. ESC “Full Off” mode is intended for off-highway or off-road use only.
Traction Control System (TCS)
The TCS monitors the amount of wheel spin of each of the driven wheels. If wheel spin is detected, the TCS may apply brake pressure to the spinning wheel(s) and/or reduce engine power to provide enhanced acceleration and stability. A feature of the TCS, Brake Limited Differential (BLD) functions similarly to a limited-slip differential and controls the wheel spin across a driven axle. If one wheel on a driven axle is spinning faster than the other, the system will apply the brake of the spinning wheel. This will allow more engine torque to be applied to the wheel that is not spinning. BLD may remain enabled even if TCS and Electronic Stability Control (ESC) are in reduced modes.
ferraiolo1
Spends too much time on here
Yes it does, automatically
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