i've heard a lot of different thoughts on tranny fluid for my 727, atf+4, dexron 111, type f, does anyone have a preference. also my tranny will not be completely drained (just from the pan) so i don't know about mixing something different with what i currently have in there. by the way i don't know what's in there now. JZ. sorry, also what about putting in an additive of some sort, is it worth it, does it help. and how about synthetic. thanks.

F furr me .... better shifting qualities ..

The fluids you have listed are all fine. I use dexron/mercon. Also you should drain your torque converter. You only need to remove the shield in front (4 bolts) and then rotate the converter to find the hex plug. Lots more fluid will come out, that way you replace most of it . Additives are not needed/nec. IMO

For a 727 i like to run type f. I have a non lock up A-518 that i run dexronIII in. I asked about running type f in an A-518 and members here told me that type f would not lubricate the planeterys that are always running in the A-518 transmission. So i decided to run dexronIII. But in a non overdrive 727 i'd pick type f hands down.

Some people mix dexron and type F. I just use straight up type F.

And i forgot to add i wouldnt be too worried about just dropping the pan and putting type f on top of whatever is in there, wich is most likely dexron of some kind. If it were me i'd just get 18 to 24 qaurts of type f, drop the pan change the filter and put a new pan gasket on and re-fill with type f, then drop the pan once every week or two and just keep re-filling with the type f and by the time you do that 3 or 4 times you will most likely have all the old fluid out and have new fluid in.

i appreciate all the advice. thanks so much.

Dexron III had the later stuff all have more viscosity improvers than Type-F. That's why Type-F shifts firmer and is recommended for high mileage transmissions. It helps to keep the clutches from getting glazed and slipping sooner.

Me, daily driver = Dexron III, street/strip fairweather fun car = Type-F.

"F" in all my TFs.

mix all the time,no ill effects.im sure you will hear no to do this,but ive never heard of a failure from mixing f,dextron,ect

I don't think you have to worry about trans failures when mixing fluids. You just lose the benefits of type F when you mix it. I have run dexron or type f in my cars.

I am currently running atf + 4 in the 904 in my 83 cordoba b.c it reduces the torque converter shudder when it locks up.