Use your favorite brand,dextron 3 ..this is a rugged transmission ,you could run auto store brand,any product you buy will be superior to the original fluid,the fiero automatic transmission is one of its good points.
Things you need to know about ATF. It Lubricates, carries heat away from tranny, cleans tranny parts, is a hydraulic fluid. But most of all, Old fluid carries dust particles that help grip the clutch packs as the friction discs wear. This is why sometimes you can total a tranny by changing the fluid (on some cars) High mileage low maintenance.
Posts: 1282 From: Lawrenceville, GA USA Registered: Sep 2006
I put Mobile 1 synthetic Dexron III in my 86 auto several months, maybe a year ago. It's been running perfectly all this time. It was my daily driver until I got my 88 duke in July, which has been my daily driver since August.
"What is the best fluid to use in my 86 2.8 automatic tranny ?"
That's all depends on what are you doing? What driving style? Racing or just plain old grocey getter.
For the performance minded (racing). Either Trick Fluid or good old Ford F-Type. must have an additional trans cooler for the higher friction fluid. Will wear out the interal compnenets in no time. Should change out fluid and filter at least once a year or after the racing season.
The regular grocey getter: Good old plain Dextron III fluid. should change the fluid at least once every 30,000 miles.
All post good advise ,this is a place where you can go with lowest price ,use of fluids depend on mind set.. if you are use to using a brand name oil just use there ATF.. the 3 speed auto is not fussy,when a transmission gets 20 years old,it needs more frequent fluid change, the t125 in the fiero needs no special treament its a work horse,, your transmission is probably the original and has probably never been worked on ,it is full of crap(tech term) from years of use.. the T125 is not a good tranmission it is a reliable transmission..if it were mine ?? I would run the cheapest atf I could find for 500 to 1000 miles drain it and install what you prefer.. my post on t125 are not based on my own experience ,but on study ,reading ,listening to mechanics and talking to owners,and work on other transmissions! wish I could say same about 4 & 5 speed! ha ha