BW48-11 to 48-12 Swap

[pmb2024]

Hi everyone!

I drive a 2021 Ram 1500 (US spec, Built-to-Serve edition) based in the UAE. The truck came with the BW48-11 transfer case, which features a 4WD Auto mode. Around 60,000 km, I began receiving repeated 4WD Overheating warnings during desert trips. Eventually, the transfer case completely failed to engage 4WD, and I had to be recovered from deep in the desert since I couldn't self-recover in 2WD through soft sand due to the weight of the truck.

Diagnosis:
Visited two shops — both confirmed:

• Actuator is working
• Transfer case clutch is not engaging
• 4WD modes try to engage (as shows as 4wd engaged) but only rear wheels spin - regardless of 4H or 4L, or diff lock.

Through further research, I learned that part-time transfer cases tend to be more reliable for heavy off-road use — which fits my use case. I didn't want to part ways with my truck because of this and get a Rebel so eventually I came across examples of 4th-gen Ram owners swapping BW44-44 (4WD Auto) for BW44-45 (part-time) for this reason. When I checked my model, I found that my truck uses the BW48-11, and its part-time counterpart is the BW48-12. Mopar's official parts site confirmed this match, so I ordered a BW48-12 transfer case from the US, assuming the swap would be similar to the 4th-gen swap process.

• Current TC: BW 48-11 (Part #68250775AG)
• New TC: BW 48-12 (Part #68535808AA)

The Challenge
Once the new BW48-12 arrived, I took it to a local shop with experience working on Rams. They told me the transfer case’s electrical connector doesn’t match — the new BW48-12 uses a different plug and pin layout. From what I’d seen in the 4th gen swap, it’s common to re-pin or rewire the connector, so I expected that to be part of the process. However, the shop is unsure, saying that the wiring differences suggest the transfer case might function differently altogether and saying this is completely the wrong part. I’m not fully convinced and believe the issue might still be resolved with correct wiring — if we had the right diagrams.

In short:

• Did I really purchase the wrong transfer case, or is this just a wiring mismatch?
• If this is the correct part can anyone share wiring diagrams for:
  • BW 48-11 (Part #68250775AG) - I believe this has a 7-pin connector.
  • BW 48-12 (Part #68535808AA) - I believe this has a 6-pin connector.

I am thinking also about making a simple plug-in harness adaptor between the new TC and the truck so it's a cleaner solution than unpin, and easier for any shop to install.

TL;DR
I am trying to swap a faulty BW48-11 transfer case in my 2021 Ram (UAE-based) with a BW48-12 for better off-road reliability, but now facing wiring mismatch issues. Need help confirming compatibility and wiring diagrams to complete the swap.

 

[Marine6212]

Connectorexperts.com should have the parts you need to make a splice in harness.

 

[Bt10]

Does the auto style overheat in 4hi mode? I.e. not running the clutches often. Might simply replace and use locked in 4hi?

Sorry, no help on the wiring. Good luck. Tradesman is no 4auto also.

 

[kapinallinen2]

if we had the right diagrams.

Might have to re-program vehicle config?
Not sure if these help, wondering why one schematic has the 3 pin connector.
Apologies for the lack of resolution, they get compressed a lot when uploaded.

 

[pmb2024]

Connectorexperts.com should have the parts you need to make a splice in harness.

Thanks!
Any idea which connectors I need to look at? Or how to find out

 

[pmb2024]

Does the auto style overheat in 4hi mode? I.e. not running the clutches often. Might simply replace and use locked in 4hi?

Sorry, no help on the wiring. Good luck. Tradesman is no 4auto also.

Yes it was also overheating in 4h

 

[pmb2024]

Might have to re-program vehicle config?
Not sure if these help, wondering why one schematic has the 3 pin connector.
Apologies for the lack of resolution, they get compressed a lot when uploaded.

Thanks for this! There is an extra connector on the old TC, see photo. Could that be the 3 pin connector? I assumed it was a sensor required for the 4wd auto not needed/present in the new one.

Any chance you can send the DH8 schematic in better res? The other one is clear.

Edit: yest I believe it will need programming but I should be OK to do it in Alfaobd