Thoughts on XL-12 Transfer case fluid | Ford Explorer Forums - Serious Explorations

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Thoughts on XL-12 Transfer case fluid


Well-Known Member
March 1, 2017
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City, State
Year, Model & Trim Level
2004, 4wd, 4.6l
The last time I changed the fluid in my t-case I used a dex/merc III ATF. As instructed in my owners manual. Someone piped up and said that I should really be using Ford Mastercraft XL-12 T-case fluid.

I am going back in there and changing out a bunch of fluids before the winter and figure I should maybe change out the t-case again. Is xl-12 the best thing to us. It is said that xl-12 has friction modifiers to help engagement. However it is my understanding that the T-case uses a mechanical ball and ramp type engagement and not a tradition friction clutch plate.

If using a special t-case fluid why not a fully syn fluid like the valvoline T-case fluid which says it is suitable for xl-12.^c-plaid^66418499719-sku^46KK34-adType^PLA

I keep wondering about this since mine asks for Mercon v. I wouldn't use xl-12(Mercon) in a TOD transfer case such as my 4411. From my research it won't matter much though. Even makuloco states xl12 not for TOD.

Last time I changed fluid in my 2G I refilled with the Valvoline. DexMerc is good too.

OP the clutch does have frictions & steels, and they are engaged via the ball & ramp.