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Changing AW4 transmission fluid...

C

CLTSV650

NAXJA Forum User
Location
Richmond, VA
I've searched around the forum and read the manual, but I didn't see any specific details on changing the fluid. So here's what I did:

1. Wait about 30 minutes after tranny had reached operating temperature
2. Drain it all out
3. Replace drain plug
3. Put 4 quarts Dexron III/Mercon thru dipstick tube.
4. Run it around for 10 minutes, shifted fine.
5. Put in Neutral, check level

I wiped it and checked a couple times and it always came up to the zig-zag portion of the dipstick. I let it sit overnight and checked it stone cold and it's still up to the zig-zag part of the dipstick.

Did I overfill? What's the easiest way to remove fluid? Crack the drain plug a little? Thanks in advance...
 
Yeah, it holds way more fluid than you can get out by draining. This also means that you aren't really "changing" the fluid by doing what you did, you're just mixing a little new fluid with a lot of old.

You might want to do a couple more drain and fills to effectively change a bigger percentage of the fluid. There are ways to drain nearly all the fluid but they are a PITA, so what I usually do is drain and fill, drive 50 miles, then drain and fill again, drive 50 miles, and then once more. This effectively changes like 75-80%, I think.
 
92xjsp said:
Yeah, it holds way more fluid than you can get out by draining. This also means that you aren't really "changing" the fluid by doing what you did, you're just mixing a little new fluid with a lot of old.

You might want to do a couple more drain and fills to effectively change a bigger percentage of the fluid. There are ways to drain nearly all the fluid but they are a PITA, so what I usually do is drain and fill, drive 50 miles, then drain and fill again, drive 50 miles, and then once more. This effectively changes like 75-80%, I think.
Click to expand...
yup getting 100% of the old stuff out really is a pain in the ace, ive a nice little scar on my finger from when i changed my trans filter and gasket
 
I use an old rear windshield washer pump (12 V, I found in a ford station wagon at the junk yard) hooked up to a long cord and couple of alligator clips big enough to fit over the battery clamps and small tubing to pump excess oil out of the dipstick tube, works for me.
You can also do the same thing with a battery filler bulb (enema bulb) and a long piece of tubing. I use clear aquarium tubing.
Getting the plug out and finding the threads again quick can be iffy and messy.

Keeping a twelve volt pump around comes in handy. I got tired of throwing away loads of differential oil after deep water fords. Now I pump it out and then pump it back in again, if it still looks fresh and water free. You just have to get it warm before you try the pump.

Dexron is fairly cheap, I change the oil every spring, figure every 3 or 4 years it all gets replaced. The torque converter holds a bunch of oil where you can't easily get at it.
 
Last edited:
The easiest way to change the trans. fluid is to do a poor mans flush. All you have to do is remove the return line from the soft/hard connection, place it in a bucket and have someone start the vehicle. When the fluid starts to sputter, shut it off and put in clean fluid through the fill tube. Continue the procedure until it runs red. Easy! On the '99 XJ's, the return line to the trans. is the top line that enters the rear of the transmission, don't know about the others. Hope that helps.
 
tangowhiskey said:
The easiest way to change the trans. fluid is to do a poor mans flush. All you have to do is remove the return line from the soft/hard connection, place it in a bucket and have someone start the vehicle. When the fluid starts to sputter, shut it off and put in clean fluid through the fill tube. Continue the procedure until it runs red. Easy! On the '99 XJ's, the return line to the trans. is the top line that enters the rear of the transmission, don't know about the others. Hope that helps.
Click to expand...

Any thoughts on this?
 
Plays For Jeeps said:
Any thoughts on this?
Click to expand...
easy, works, and have done it many times to wifes Dodge neon since the tranny in the Neons are absolutely the best design and most dependable tranny on the road ..... yeah right!!....(ouch that was such BS I think I can taste it!!)
Either way I change the fluid like this every 3rd oil change and amazingly this POS has lasted 200k on original tranny.....which if you know the history of DC trans. that is a miracle from heaven!!! :)
 
Blaine B. said:
How much fluid does the AW4 trans pan hold?

I hear the entire system is somewhere around 8 quarts.....with 3 or 4 in the trans pan? Is that right?
Click to expand...

"Service" fill (drain and fill at regular intervals) is right around four quarts.

"Dry" fill (fill after overhaul and replace torque converter) is around nine quarts.

A "minor overhaul" will typically take five to five and a half quarts, assuming the TC hasn't been drained. Safest is to put in four quarts, idle the engine while shifting through all gear ranges (at least 30 seconds in each range to fill the valve body - 30 seconds going down and 30 seconds coming up) and check/fill as needed afterwards.

That crosshatched zone on the 'stick is the "nominal full HOT" range - as long as you're in there, you'll be fine. "Full HOT" is a bit higher than "full COLD" due to fluid expansion - but "full COLD" is usually right around the bottom of the crosshatched area on the dipstick in most cases. So, it's entirely possible that HOT check and COLD check will both be in the crosshatched area - and they could, in fact, be the same level (even though HOT fluid will expand, you're still checking it with the transmission running and fluid circulating - so the volume you gain from fluid expansion may be made up for by the pump running and suchlike.)
 
Correct me if I am wrong.....

When the Jeep is running, but in park, fluid is flowing though the AW4. The Jeep does NOT have to me moving for the fluid to be cycling though the system.
 
the_weirdo said:
True.
Click to expand...

But the transmission should have been operated (read as driven) for at least 20 minutes before checking the fluid level in PARK.
 
tangowhiskey said:
The easiest way to change the trans. fluid is to do a poor mans flush. All you have to do is remove the return line from the soft/hard connection, place it in a bucket and have someone start the vehicle. When the fluid starts to sputter, shut it off and put in clean fluid through the fill tube. Continue the procedure until it runs red. Easy! On the '99 XJ's, the return line to the trans. is the top line that enters the rear of the transmission, don't know about the others. Hope that helps.
Click to expand...


This is how I change the fluid on my 2000. With the engine off and the tranny fluid at operating temp, I just open the system at the tranny cooler, behind the front bumper and clamp on a 2' piece of hose to the return line (the one with the hose clamp on it) and drop it in a drain pan. Proceed as stated above.......this process will also cycle the old fluid out of the torque converter. Check your fluid level and recheck after you've driven enough to get your trans fluid back up to operating temps.
If you just drain the pan and refill, you are simply diluting the old fluid with new.

A commercial pressurized "power-flush" is a great way to force a tranny rebuild, fwiw.
 
Last edited:
FWIW, it may be wise to change T fluid in multiple small steps. That way if there is varnish in the Tranny it is slowly loosened and slowly circulated, diluted, and drained in multiple steps. An all at once or 50/50 change can loosen all the trash and junk at once that lodges in small tight places, clogging things up, like in the valve body. That is why I never let others "service" mine with a so called flush T fluid change.

Mine, 87 and 89, only drains 2.5 quarts out a time using the drain plug. AW4. That works out to 25% change of the net volume each time.
 
I know this is an old thread; however I was reading it and had some questions. I have done multiple transmission fluid drain and fills on my 98, and It seems if I put more than a little over 2 quarts in after draining the pan then it reads high (but I have been checking in Neutral). When others have done this (drain and fill), is everyone else in agreement that 4 quarts needs to be refilled after draining the pan. If not, how much have you guys been adding of Dex/Merc III. Thanks for the insight.
 
it is around 2-2.5 quarts for a drain and fill. I usually drain and fill the pan 2-3 times a year and simply dump about 2 quarts in there. I also run a tranny cooler in front of the radiator which I will sometimes drain that and the lines. Doing the pan drain and fill a few times a year is cheap insurance to keep an eye on the fluid color, smell, and metal in the fluid, and piece of mind that you are keeping the tranny in halfway decent shape.
 
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