2021 Ram 1500 Laramie 4x4
Transfer Case swap from BW48-11 to BW48-12
Please note, this write-up was created using Microsoft Word, then copy/pasted into this format. As such, the diagrams are added as attachments. I will also be attempting to attach a PDF of the write up. Please let me know if you have questions.
Transfer Case swap from BW48-11 to BW48-12
Please note, this write-up was created using Microsoft Word, then copy/pasted into this format. As such, the diagrams are added as attachments. I will also be attempting to attach a PDF of the write up. Please let me know if you have questions.
Background
Starting in 2019 with the introduction of the 5th generation Ram 1500 platform, Ram offered different transfer case systems depending on how the truck was optioned/trim configuration.
- BW 48-11 transfer case: offered the ability to select Auto 4wd, 2wd, 4hi, and 4lo. This unit operates using a series of clutch packs to deliver power to the front and rear driveshafts. This option does have benefits, primarily in loose surface pavement driving applications (icy or slick pavement). The system is automatically able to engage and disengage the front driveshaft to deliver maximum traction and stability. This t-case is generally found in the Bighorn, Laramie, Longhorn, Limited, and some Rebels.
- BW 48-12 transfer case: This is a more traditional part time transfer case offering 2wd, 4hi, and 4lo. It is chain driven and is truly locked when in 4wd providing a 50-50 split between the front and rear driveshafts. This t-case is generally found in the Rebel and Tradesmen trims.
- BW 48-13 transfer case: Exclusive to the TRX and RHO trims. This t-case is a full-time allwheel drive unit offering a 4lo selection. Like the BW 48-11 it is also clutch driven, however from my understanding it is capable of handling higher loads.
I have seen many threads online discussing the advantages and disadvantages of the BW 48-11 t-case (and its predecessor the BW 44-44). Many claim to have issues of over heating the clutches which leads to the front driveshaft disconnecting (not a true locking t-case). On the other hand, many people claim that they have never had an issue with the BW 48-11.
In my particular situation, the BW 48-11 was not up to the task. Many times while on trails in Colorado, Moab, and Texas I would receive the over heating warning and my t-case would disconnect from the front driveshaft. Depending on the situation, I might be able to let it cool down for a bit and continue. In many other situations involving ledges, no amount of cooling would keep the front driveshaft engaged. For my situation and use case of the truck, the swap makes the most sense. The chain driven BW 48-12 should enable me to overcome obstacles that were not possible with the BW 48-11.
Disclaimer: I am not a licensed mechanic or automotive engineer. You take full responsibility for any modifications you choose to perform on your own truck. I am attempting to be as detailed as possible, however, you will need to have a certain level of mechanical ability if you choose to attempt this yourself. Feel free to reach out if something is unclear in the instructions.
List of Required Items
- BW 48-12 transfer case
- Compatible Transfer Case Control Module (TCCM)
- Mopar Part number 68483995AB for trucks equipped with open differential or limited slip
- Mopar Part number 68433993AB for trucks equipped with the factory e-locker (this is my situation)
- Delphi 8 way female GT 280 Connector. Delphi part number 15326654. Available from Waytek (Waytek part number 38382)
- 18-16GA Female Terminal GT 280. Delphi part number 15304719. Available from Waytek (Waytek part number 30475)
- Yellow Cable Seal 18-16GA. Available from Waytek (Waytek part number 39036)
- 8 way TPA GT 280 Series. Delphi part number 15430896-B. Available from Waytek (Waytek part number 38755)
- AlfaOBD software and appropriate gateway and Bluetooth link (Do your own research on this if not already familiar)
- Recommended Crimping Tool: “HKS Ratcheting Crimping Tool Set 11 PCS with Changeable Jaws for Dupont JST MOLEX - Open Barrel Terminals, Insulated & Non-Insulated Ferrules, Terminals & Butt Connectors,Solar & Coax Connectors”. https://www.amazon.com/dp/B095LF1ZSV?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
- Recommended: 18-16GA male Terminal GT 280. Delphi part number 15304731. Available from Waytek (Waytek part number 30474).
- Electric tape
- 14 GA copper braided insulated wire (two of the connections will require jumper wires to extend their length for the new plug)
- Wire caps. (three of the wires will no longer be used and must be capped off)
Wiring Diagrams
Instructions
Before beginning, ensure the truck is in 2wd, on level ground, and parking break set.
- Remove front and rear driveshafts
- Remove skid plate if equipped
- Remove 8 wire harness and 3 wire harness from the transfer case.
- Using a transmission jack, support the transfer case.
- Remove all bolts for the transmission mounts (these will need to be removed to access the lower studs securing the t-case to the transmission).
- Using the transmission jack, lift up on the transfer case to remove the transmission mount and bottom plate.
- Remove the bottom two nuts from the transfer case studs.
- Reinstall the transmission mounts and lower the t-case back down.
- Remove the remaining nuts from the t-case studs.
- Using the transmission jack pull the t-case away from the transmission and lower it down.
- With the t-case removed from the truck, locate the 8 wire and 3 wire plugs.
- To ensure there is enough length in the harness to plug in the new t-case, the wires will need to be cut close to the old plug. Cut the 8 wire plug and 3 wire plug off of the harness.
- Proceed to rewire the new Delphi plug as follows. Reference Wire Diagram as needed. Note: do not forget to install yellow cable seals onto the wire prior to installing the new terminals. First, from the original 8 wire plug:
- Brown wire into position A
- Yellow wire with dark blue stripe into position B
- Yellow wire with light blue stripe into position C
- Yellow wire with brown stripe into position D
- Yellow wire with gray stripe into position E
- Dark green wire with yellow stripe into position F
- Note: the yellow wire with black strip and yellow wire with green strip will not be reused (cap these off)
- Moving on to the 3 wires from the 3 wire plug. Note: these wires will require jumper wires to extend far enough to the new plug:
- Yellow wire with dark green strip to Position G
- Yellow wire with tan strip to Position H
- Yellow wire with dark blue strip will not be reused. (cap this off)
- Once the new plug is attached to the harness as per above, wrap lots of electrical tape around the harness.
- Install the new BW 48-12 t-case by following these directions in reverse. Be sure to use blue Loctite on all t-case studs and driveshaft bolts.
- Locate the transfer case control module in the passenger side foot wheel. Remove the three plugs and two bolts holding it in. Replace with the appropriate transfer case control module as seen in the required items list.
Connect AlfaOBD to your truck (research how to do this if you are not sure).
- Connect to Body Computer in AlafOBD. From here, Active Diagnostics then proceed to car configuration in the drop down menu. Select VehConfig 3: T-Case Type to 44-45/44-46 w/Sync/44-48 w/Sync. Clear all codes.
- Connect to FourWheelDrive (not in body computer). Clear all codes. Proceed to Active Diagnostics > reset non-vital memory option > run (note, I can not remember exactly what this option was called, but I believe it will be obvious when you see it).
Note, I still have the original gear selector module in my truck, but now the 4auto button is a dummy button that doesn’t do anything. I tried installing a new selector module with the appropriate buttons, but couldn’t get it to work. In the end though, the new BW 48-12 t-case does work and shifts appropriately through each of the ranges.
Good Luck!
