Not knowing what fluid is in my automatic trans, what fluid should I buy for topping off after adding a cooler?

 

When was the last time it was changed?

 

what is your engine and transmission and year?

 

No idea when it was last changed, just got it. It is a 4.0 engine, all I know about the trans is it is an auto.

 

their is plenty of threads about this. search and yee shall find...

I run dex III or equivalent.

my 99 owners manual says:
"Using transmission fluids other than ATF+3 my cause deterioration in shift quality and/or torque converter shudder."

 

Dex/Merc III compatible is best for the AW4. Widely available.

True licensed Dex/Merc III is no longer mfg. but "compatible" is.