231 Fluid

ATF-3 or ATF-4? About 2 quarts or until is starts to dribble out on filling it?

Dex III

The transfer case is far less sensitive to the type of fluid used than the AW4 is, but ultimately you'll want to either use ATF-4 or Dex/Merc III as suggested by souske. Many prefer to use Dex/Merc III since it's what it was filled with from the factory, and is what you likely (read: should) be using in your transmission... Some fear cross-contamination between the T-case and transmission, and prefer to use the same fluid in both.

That being said, I'm running ATF-4 in mine, whilst still running Dex/Merc III in my transmission. The transfer case is extremely simple and doesn't have any components that are sensitive to the use of ATF-4, so you can feel free to use either.

Dex III is fine with me. I'm going to service my AW4 next so I can just get all the same then.

scott00tj said:

Dex III is fine with me. I'm going to service my AW4 next so I can just get all the same then.

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Matching the fluid just makes plain good sense.

FYI--there are no clutches, brakes, or hydraulic valve bodies in the transfer case--you COULD, in a pinch, use any ATF fluid.

What about using Valvoline's MaxLife Dex/Merc ATF for the 231 and AW4 (CLICK)? It says its formulated for all Dexron III applications.

scott00tj said:

What about using Valvoline's MaxLife Dex/Merc ATF for the 231 and AW4 (CLICK)? It says its formulated for all Dexron III applications.

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That is fine.

scott00tj said:

What about using Valvoline's MaxLife Dex/Merc ATF for the 231 and AW4 (CLICK)? It says its formulated for all Dexron III applications.

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Been using that for years in my XJ.