I have the motor and trans out of our 05 neon and thought about rebuilding the trans since its out even though it works ok , it has 160,000 miles on it. but i hate to have to pull it out again if it goes bad so i thought about rebuilding it to be safe. i found a master rebuild kit for $139 on rock auto. i have only rebuilt a couple old 727 and a few 4 speed A833, they all worked ok when done. and never this type. would i require special tools, or should i just take to someone who does them all the time? I dont have a pile of cash to spend right now, i did get a new filter and fluid and figures i would change that any way. do these transmissions normally last a long time?

thanks for any advice.

Would I rebuild while it was out? Yes.But I know how and have access to the tools required.

BUT A604 based transmission do require some special tools to overhaul that may not be in the typical mechanics tool box.
such as spring compressors for the 2-4 clutch , another one for the low-rev clutch and piston assembly guides for the OD-UD clutch packs.

If you don't have access to said tools and/or are familar with the internals of a A604 based trans either find someone who does , or leave it alone.

A604 based trans are a completely different animal than your typical 904-727 based variants and may or may not be easy for everyone.

604 based transmissions have 3 driving clutches and 2 holding clutch sets ( no bands ) which makes for lots of snap rings,seals, clutches and steels and most are not interchangable even thought they may look similar