Do not flush, over the next 3-4 oil changes just drain as much transmission fluid as will come out from the drain plug and refill. Flushing can cause dirt to break loose that is not hurting anyting right now but can damage if it comes loose. It normally takes around 3-4 oil changes for the fluid to start looking good again and you are set.

Use Dex Merc lll for the fills.

 

There is no problem with flushing it as long as you use the transmission pump to pump the old fluid out, while you are adding new fluid, don't use a machine to flush it. You can cut either one of the soft lines towards the front then put a drain pan underneath and have someone start the jeep real quick so you can see which way the fluid is flowing. Then you just clamp your hose on it, and run the jeep while slowly adding fluid untill the fluid coming out looks clean. Then you put the hose back together with some barbed fittings and hose clamps. Of course there is nothing wrong with the drain and refill method either, but if you do it this way you can get it all at once.

 

 

I think the drain plug takes a 14mm wrench. About 4 quarts will drain. Replace the lost fluid, drive for X amount of time, then drain again. When the color turns back to a decent red, your done. Use DexMerc III

 

Listen to tuna^^^.

 

Agreed. Don't use a machine flush on older transmissions. Doing this gradually is much more gentle and less likely to kick-up all the crud that can damage the internals. Be sure to clean your pan and replace filter during this process. When I did this before I rebuilt my AW4, I drained, replaced filter, and added the 4 quarts that drained out. Drove it about 100-200 miles, then drained and filled again.

While your at this process, go ahead and change your transfer case fluids too. Uses the same Dex/Merc III as your trans.

 

I agree with all of the above except for replacing the screen and pulling the pan. The AW4 was built to not need that.

 

IDK, I've had my local trans shop flush several of my auto transmissions with no issues at all.

 

AW4s?

If so, how many miles?

 

3 AW4s. Around 150k.
Also Ford and BMW.

 

This is the best way of doing it by far since it will get all the AT fluid changed at once, including torque converter, oil cooler(s) and lines!

I hear what cruiser54 is saying about no need to remove & clean the pan and he may be right, but I would still remove the pan first and clean it since it's unknown if it was ever done by the previous owner.

Just saying

🤔

 

 

This identifies the AW4's two AT fluid lines:

(Should be easy to find convenient spot do disconnect somewhere close to radiator / AT cooler)



The author is someone else on one of these Jeep forums!

 

Post a pic of the screen you remove please.