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NP 231 Drain Plug


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My NP 231 has an odd drain plug - the 30 MM socket won't fit due to clearance issues with the case, and I can't figure out what type of inner hex/square/torq fitting I can use to get out the middle.

 

 

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I have never seen an NP231 with a Torx headed plug.   It's a Allen type (hex socket) that may be bunged up by previous "repairs".     Start by cleaning the crud and corrosion from in the hex hole, and use a pick or the like to clean the corners of the hex.   Then you can do a trial and error search for the best SAE or metric allen socket to fit it.

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I guarantee it came from the factory like this. 

It's 8-point something.

Nothing has bunged up.    I tried to fit a 30MM on it and turn it, but not enough clearance between the housing and bolt to fit the socket correctly (snugly).

 

 

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15 minutes ago, JustEmptyEveryPocket said:

Why do you guarantee it? I'm genuinely curious because personally I have not seen this type of plug. Not that I have seen more than 3-4 NP 231s.

 

Because we have had this jeep since new.   Never changed trans, or diff fluids.   

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I am glad you got it out., and I will admit, I find that plug quite amazing.   I have seen allen plugs, and hex head plugs, but never an eight-pointed plug.  (Notice carefully it's NOT a "Torx" shape, which has curved tips of the "points" of the star shape.

 

Maybe one of our "seasoned" Jeepers can comment if this was ever a common type of plug.

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23 minutes ago, WesD said:

New fluid in, transfer case linkage adjusted.

It's stuck in 4H.   

Can't get it to pop back into 2H.

Any ideas?

 

 

Can you jack it up so all the wheels can turn by hand, and then have some helpers turn those while you fiddle with the linkage?

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Here's how the factory suggests you shift the transfer case and I've been doing this since these things were new and I worked at the dealership. Quoted from the owner's manual. The suggestions in CAPS are mine. 

"To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed". I LET OFF THE GAS, THROW THE LEVER, TAP THE GAS AND LET OFF.

4L position: " To engage, slow the vehicle to 2-3 MPH , shift the transmission to Neutral, then shift the transfer lever to the right and pull firmly rearward to 4L". 

TO SHIFT OUT OF 4L, SHIFT THE TRANSMISSION INTO NEUTRAL WITH THE VEHICLE STOPPED, SHIFT THE TRANSFER CASE LEVER TO 2H, THEN THE TRANS TO D IF YOU HAVE AN AUTOMATIC, OR INTO FIRST GEAR WITH A MANUAL, AND CONTINUE ON.

Revised 11/20/2014
 

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I tried exactly that.   Numerous times.

I've tried everything thus far.

 

Going to do one more fluid flush and see if that helps loosen it up a bit.  

Shifts between 4H, N, and 4L just fine.

 

 

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