Hi y'all. These forums have been real helpful when I've done maintenance on my 97 Jeep XJ (217k miles so far...) which I've had about 5 years so I thought I'd return the favor by posting a chart that I made which I think is helpful.

I recently checked my notes and saw that.. well, let's just say that a transmission fluid change was overdue in my 1997 Jeep XJ.
I decided to do a few partial transmission fluid changes by opening the drain plug and letting the fluid drain out and refilling through the dipstick instead of dropping the pan.
The downside of this method is that you will not be able to change the transmission filter (if that is something you think is necessary), and you won't get to experience the fun that is changing the gasket 😛.
The upside I see is that this seems more "gentle" of a process (especially compared to a flush which lots of people recommend against for older vehicles).
In the AW4 Automatic Transmission version of the Jeep XJ only about 3 quarts of ATF drains out if you do NOT drop the pan.
The full ATF (Automatic Transmission Fluid) capacity in the AW4 is supposedly 8 to 9 quarts, so doing a partial change of the transmission fluid without dropping the pan only changes about 1/3 of the fluid.
**NOTE*** use an EMPTY bucket to catch the transmission fluid that you are draining so that you can measure the quantity that is removed for reference!
The specified torque I find for the transmission drain plug bolt is 20ft*lb (240in*lb), but lots of people say just to hand tighten it.
Then whatever fluid amount needs to be replaced through the transmission fluid dip stick opening afterward. In my case, 3 quarts were drained but only 2.5 quarts were needed for refilling. Don't ask me why.
Most people recommended using Dex iii / Dex 3 / Dexron iii, BUT it also seems safe switching or transitioning to Dex vi / Dex 6 type ATF from Dex iii. I haven't heard about any issues that anyone has had after switching to dex vi and it is supposed to be compatible with dex iii.
Then, of course, the transmission dipstick should be used while running in neutral to make sure that the level is in the safe range.

If you do a number of partial transmission fluid changes, eventually you will reach a point where most of the fluid is new, as shown in the chart below where I made the calculation to see how many partial changes it would take.

Partial ATF transmission fluid change chart.

I think this chart makes a pretty good case for doing this kind of partial transmission fluid change every 1 or 2 oil changes if you are using a full synthetic (or maybe every 3 or 4 oil changes if you're still using conventional oil) if you want to keep your transmission fluid fresh.

In my case, I was overdue for changing the transmission fluid so I did a partial change of 3 quarts through the drain bolt 4 times within the past 4 weeks driving a few hundred miles between changes (using 12 qts so far) to reach 80%+ new fluid), and after that I plan to start doing the same partial fluid change of 3 qts with every oil change (I use full synthetic motor oil for about 10k miles or 12k miles between changes (mostly highway)).

Hope this helps somebody!

 

Factory recommendation was drain and refill every 30,000 miles under normal service and 15,000 miles for severe service. Examples of severe service include postal delivery, taxi etc.
Use only Dex/Merc ATF!! There is NO service interval for the "filter" which is actually a metal screen.
Hand tighten the drain bolt using a new crush washer each time.
This transmission is one of the most robust automatics ever produced.
The color and smell of the fluid tells the whole story.
FWIW, every other auto trans out there does not change all the fluid with each service even with pan removal. That is factored in by the engineers. They know you'll not be changing ALL the fluid each time.