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Best AT fluid?

riverside

NAXJA Forum User
Location
Riverside CA
My 92 XJ with 180,000 miles is due for an AT fluid change. What fluid works best, and any advice as to how to drain as much fluid as possible? Thanks
 
I'm thinking Royal Purple or Amsoil, any reason why I should not use either of these? (other than cost?)

I run Amsoil, but I have since I bought the Jeep brand new. When I installed my shift kit a couple yrs ago the pan was spotless!
 
If you change the filter, it seems to drain more fluid out. Note that means taking off the pan. I want to say, I had to add 5 quts when I took of the pan. I think 3- qts, when just drained. I use NAPA DEXTRON/MERCON. I'd also probably drain a few times and be happy. I've taken off the pan of 3 or 4 XJ trans. One had black stuff in the pan, 130K. Two others were fairly clean, over 200K. I'd also think about adding a trans cooler.
 
I would say it depends on the condition of the current fluid. If the fluid is old, dark, and burnt then you will be better of changing it several times every few hundred miles until it comes out clean. I would just drain the pan and refill using commonly available Dexron III ATF that you can get a Walmart, NAPA, or wherever you buy parts. Valvoline and Wal Mart Super Tech work just fine. It typically takes 1 gallon on flat ground. Removing the pan on these transmissions can be a headache because the dipstick is connected to the pan. The "filter" is nothing more than a fine metal screen. These transmissions are one of the most durable transmissions ever made and routinely outlast the 4.0L engine. Going 300-400K without dropping the pan is not uncommon at all. I drain and refill my transmission every 20,000 miles. It's not expensive and works for me.
 
I have used this method for decades to flush the transmission when not changing the filter. It gets out just about all the old ATF. M
Mercon III, from Napa is all that has been used in my XJs over the last 16 years.
Buy a case of it.

Drain the pan and refill with fresh ATF.
Pull the cooler return line and connect it to a clear hose. Stick the end of the hose into a 1-gallon jug.
Start and idle the engine until 2 quarts or so comes out and then turn the engine off. A helper is useful but not necessary, as the oil is not pumped out very quickly when idling.
Add the same amount of ATF to the transmission filler as what was pumped out.
Make sure to keep an eye on the jug so you do not overfill it.
Repeat the above until the fluid, in the hose, changes from a dirty color to clean. You will see the difference.
Top off the trans fluid, reconnect the cooler line and you are done.
Seal the jugs of used ATF and recycle them at your local auto parts store.

It uses a couple quarts more than what the FSM says the trans holds as the extra ATF flushes the old oil out of the torque converter.
If done right, there is nothing about this that can cause the transmission harm.
It is not the same as power flushing.
 
Sounds good, which line of the cooler is the return line?

The line at the bottom of the transmission.

I run Amsoil, but I have since I bought the Jeep brand new. When I installed my shift kit a couple yrs ago the pan was spotless!

Very interesting indeed.

There are about 10,000 posts online indicating that anything except the old fashion ATF-2 or is it ATF-3 will cause the AW4 to spontaneously melt down into a fiery red heap of molten aluminum and what ever else the AW4 choses to spit out.

My XJ is sporting over 330,000 miles. All oils except in the rear diff (as a request of Auburn ECTED) runs Amsoil since about 135,000 miles. I am yet to experience a negative effect.

Do not try this (at home) in your XJ. It may exhibit negative temper tantrums.
 
I keep a gallon of the Valvoline Dex/Merc on the shelf at all times as part of my in garage parts supply. I use the "severe duty" mileage out of the manual and drain the pan and top it off every 12k miles. NO sense in overthinking it. I'd be hesitant to use synthetic if you're just now changing the fluid after almost 200k miles.
 
The "best" AT fluid, is clean AT fluid.


I keep it simple, whatever Dexron-III/Mercon is on sale at WalMart or the Farm and Fleet store, and drain/refill the pan every spring. Any "new" XJ's get the pan drained/filled a couple of times so all the fluid is fresh.

Amsoil is probably fine to use, but is an unnecessary expense.
 
The "best" AT fluid, is clean AT fluid.


I keep it simple, whatever Dexron-III/Mercon is on sale at WalMart or the Farm and Fleet store, and drain/refill the pan every spring. Any "new" XJ's get the pan drained/filled a couple of times so all the fluid is fresh.

Amsoil is probably fine to use, but is an unnecessary expense.

I agree. Normal maintenance is all you need to worry about.

I swap mine out every other year in an even year just because I can.
Trust me if there was not a drain plug I would not do it so often.

That being said a new vehicle or new tranny I might be tempted to run the more expensive Amsoil.
 
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