I drained & filled the NP231 over the weekend for the first time since I've owned my XJ. Gear oil drained out. I poured about 1/2 a quart of Dex/Merc in there with the drain plug out to dilute and drain any remaining gear oil.

After that drained out, I replaced the drain plug and poured Dex/Merc in until it ran out of the fill hole. I was only able to get 1 quart in there. I'm pretty sure the NP231 specs are for about 2 quarts of fluid. Is there usually nearly a quart that doesn't drain when on level ground?

 

The FSM for my 95 specified 1L capacity (so just over 1 quart) IIRC.
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Duh. I don't know why I didn't check the FSM... I just went by the opinions of all the web "experts" for the capacity. Serves me right... I just checked the '00 FSM and it says 1.2L.

Thanks Pat.

 

No problem. The spec was definitely lower than I expected when I changed the fluid a few months back. I guess they say 2 because you'd have to buy 2 quart sized bottles... lol.

 

I remember reading on some older mopar spec sheet that had it listed in pints… holy the 'murican auto industry uses quarts and gallons! Pints are for pubs.

 

I don't know if mine has ever been serviced, it's a 1993 at 170K. What do you guys use?

 

I use a 10mm hex and Dex/Merc. I hope that answers your question.

 

My 95 has the real big plugs (like over an inch hex head.. I can't recall the exact size, but I had to buy the socket) and I just use the cheapo Walmart brand (SuperTech) Dex/Merc 3. Most folks seem to agree that the NP231 isn't picky about fluid so long as it's changed on schedule and the SuperTech fluids are actually pretty decent.

 

Oh, that's right about the plugs. I wasn't really sure what the question was though.

Dex/Merc is specified in the manuals and that's what I have on hand for the AW4 anyway. Any thin oil or ATF has been shown to work in the 231 just don't use anything thicker than 5w-30 or the internal pump won't be able to pump it properly. Some guys want to put 15w-40 HDEO or gear oil in them, and that's a no-no. The PO put engine oil in mine and I ran it that way for 70K miles with no issue.

With that said, just make it easy on yourself and use the recommended Dex/Merc and don't overthink it!

 

Hahaha, I should have clarified - the NP231 doesn't care what brand/type of Dex/Merc ATF you put in it (or in other words, you don't need some fancy synthetic or specialty fluid) but definitely go with the factory recommended Dex/Merc 3 ATF.

 

i cant get more in then 1 quart and a little over just 1 didnt fill it up completely

marc

edit: either the 231 or the 242 seem to take exact same amount

 

30mm socket

 

I used Valvoline transfer case fluid, which said it was compatible with transfer cases that require DEX/Merc. When I drained my transfer case I got slightly over a quart as well.

 

Sounds about right - you'll have to let us know how that Valvoline works for you - I've never heard of it until now.

 

Will do, normally 10 dollars a quart, but couldn't beat the sale they had 2 for 10!