Programming JK PCM to Recognize 4:1 Transfer Case

Does anyone know if Jeep dealers can program the Wrangler JK Powertrain Control Module (PCM) to accept a different transfer case ratio for late model JKs?

I just installed a 2013 Rubicon transfer case into my 2013 JK Sport. I'm experiencing an RPM limitation problem while in Low 4. This is a known issue for late model JKs when transplanting Rubicon transfer cases into a Sport model. At least for those with automatic transmissions. I took my JK to a local dealership but the mechanic said he didn't think his factory diagnostic tool could actually program the new ratio. He did say that he'd be willing to give it a try if he knew how to do it.

I'm aware that there are other programming options out there like waiting for the new AEV Hemi Procal, getting a Superchip Flashpaq, or shipping the TCM off to Dakota Customs to name a few. I'm looking for 'while you wait' instant gratification from a dealership if possible.

Thank you.

My dealer explained to me that they can only (or are only willing to) adjust PCM for chrysler parts. Since this is a Rubicon part, it should be okay. I don't see why they couldn't. I asked if the dealer had a price (while shopping around) to upgrade to 4.88 gears and they pretended they didnt even know what that meant because it didnt come stock.

I know that the traildash for earlier models allows you to adjust for transfer case changes. Rumor mill has said its coming soon and I've also heard its available already with a update, but I couldn't find hard evidence of that being the case.

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JKWrang said:

My dealer explained to me that they can only (or are only willing to) adjust PCM for chrysler parts. Since this is a Rubicon part, it should be okay. I don't see why they couldn't. I asked if the dealer had a price (while shopping around) to upgrade to 4.88 gears and they pretended they didnt even know what that meant because it didnt come stock.

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Thanks. My question wasn't about dealer willingness. They are willing but don't know how to change the ratio since they've never done it before. I'm trying to locate a dealership (or someone) who understands the process for setting the transfer case ratio in the PCM to 4:1.

I'm pretty sure a procal will do it as well.

OverlanderJK said:

I'm pretty sure a procal will do it as well.

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There ya go, if a procal can do it, that's probably your cheapest bet!

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OverlanderJK said:

I'm pretty sure a procal will do it as well.

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Unfortunately, the current AEV Procal cannot set transfer case gear ratio. In addition to owning one, I spoke with AEV on Monday. Their new "AG Level" Procal for the Hemis can do it but they haven't been released to the buying public yet. Something about still needing user manuals. Could be weeks or longer. Sigh.

Do it with Superchips Flashcal

Closing the loop. Just purchased the Superchips Flashcal. It took less than 5 min to make the change.

The latest version of the AEV Procal (rev G) can do what you ask. I suggest calling AEV tech support to find out the particulars. Previous versions could not do what you want.

(part number 30406007AG is what you want). If you buy from one of the vendors, make sure they are sending you the current version (this recently changed, like a month ago, and I am certain there is old stock floating around).