HOW TO: Change Transfer Case Fluid

Discussion in 'How To' started by 2003KJ, Dec 1, 2006.

  1. Dave

    Dave Administrator Administrator Moderator

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    ^^^Yup, Both t-case and tranny take ATF+4.........nothing elce or there will be trouble. It is synthetic.

    Dave
     
  2. Powerslave

    Powerslave Banned

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    Internal cooler, or External? I have a transmission cooler mounted on front of the A/C condenser, and the lines run back. I didn't look, but I didn't see any lines going into the T-Case. I hope that small thing isn't for just the automatic transmission, it looks like a heavy-duty cooler, which ALONE isn't enough for Chrysler transmissions. Aren't they supposed to go through the rad, then out into a cooler? I did that with my former car, a medium duty AFTER the rad.

    Also, an internal cooler for the T-case, and it COOLs? Just tossing that out. I really haven't gotten under the thing, I guess it's time to get it up on a lift and take a good look at what's doing under there.

    Also, damn-it, why can't they make all the fill and drain holes use the same friggin' tool? Now I gotta go get the right hex bit for the Xfer case fill and drain plugs.

    Yeah +4 is synthetic, and +3 is semi-syn...
     
    Last edited: Mar 30, 2009
  3. tjkj2002

    tjkj2002 Full Access Member

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    KJ's that have the 45RFE trans('02 and some '03's) have the trans cooler in the radiator.The KJ's that have the 42RLE have the stand alone trans cooler that you are referring to which is not enough to properly cool the trans.The in-radiator cooler can control temp spikes which the stand alone cooler can not do.I run a AUX cooler on my '02 KJ that ties into the in-radiator cooler return line to aid in lowering the fluid temps after it is stabilized in the radiator cooler,a much better set-up.

    As far as the cooler in the t-case it is all internal,there will be no lines visiable and yes it does cool since 90% of the internal space in the t-case is air and not fluid.And since the t-cases and transmissions in the KJ's are seperatly sealed there will be no cross contamination of fluids unless you have 2 seals fail.You can use any ATF in the t-case but might as well stick will ATF+4 since the trans takes the same and is less hassle if both are the same fluid,cuts down on different types of fluids you need to keep around.


    In the pic below is the inside of a t-case that is very similar to the KJ's,the red arrows are pointing to the internal cooler.
    [​IMG]
     
  4. Powerslave

    Powerslave Banned

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    Ok, so I get that, that's neat...

    I did the same with my Avenger, put the Aux cooler on the return line.

    I don't like this current Jeep setup... I would have to buy a Rad with the trans connections, then attach the cooler already there, to the return lines. Too much work, and those lines won't be easy to fool with... Maybe, one day if I get bored...

    I noticed there is no amount specified either. Should we buy one quart, or two? Although, the book would say, it's still nice to have on the first post.
     
    Last edited: Mar 25, 2009
  5. brucebotti

    brucebotti Full Access Member

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    I went to change the fluid in my transfer case, but I couldn't get the fill plug out. It looks like someone already tried, because the 10mm allen wrench didn't fit as well as in the drain plug. I only have 38,000 miles, but I just purchased it (2005 Renegade), and I would like to start with a clean slate. The F/R differentials and the transmission went fine.

    Does anyone have any suggestions? I hate too drill it out. How much heat can the aluminum case take? I was also thinking about welding the allen wrench to the plug to get it out. I'm also tempted to just leave it alone.

    Thanks,
    Bruce
     
  6. draco259

    draco259 New Member

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    I have a question, I was chaning my atf in the transfer case without reading this first, so insted of draining it from the drain plug, there was a big bolt on the bottem of the case and i drained it from that, when i took it off a spring and small bearing came out too.
    I think I put it back in right, but would I hurt anything by draining it like that rather than the other drain plug?
     
  7. Liberty06

    Liberty06 New Member

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    Exactly what I was wondering..How much fluid does this case drink?
     
  8. RageOfFury

    RageOfFury Full Access Member

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    -NV231 (Command-trac) : 1.50 QUARTS/1.40 LITERS/2.95 PINTS
    -NV242 (Selec-trac) : 1.70 QUARTS/1.60 LITERS/3.40 PINTS
     
  9. brucebotti

    brucebotti Full Access Member

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    After trying everything else, I ended up tack welding an allen wrench to the fill plug. After filling it, I replaced it with a much improved NAPA/Balkamp plug.
    Bruce
     
  10. litterfisher

    litterfisher New Member

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    Last edited: Aug 9, 2010
  11. Liberty For All

    Liberty For All New Member

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    Do it by now. I read to change every 25K miles.
     
  12. journeyjim

    journeyjim Full Access Member

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    Had some customers a few weeks ago, they worked for allison, told me they were running syn-tech in every thing as it's a real heavy duty synthetic transmission fluid. I called my mechanic about putting it into the jeeps transmission and he said no as it wouldn't work with the clutch packs.
    He told me I could put it in the transfer case so I had it done when the rest of the drive line was serviced, it seems to shift a lot smoother, I'll know more when it snows and start shifting it a lot.