I read that flushing with F-type can help the performance and increase the life of an AW71. I can't find the original post. My tranny is feeling a little slushy, it's been properly flushed and filled recently (w/Dexron).
--
88 765 w/2stage boost & G-valve @ 14 psi

I don't think filling a tranmission with the wrong type of fluid will help if that tranny is not working well in the first place. IOW, if your tranny is "slushy" from wear, Type F fluid will not help and may harm further.

That said, and probably the basis for what you read, a properly race built HD tranny, can benefit from the properties of a race type synthetic ATF, which typically meet the requirements of ATF Type F. For example, Dave Barton - has built a very fine 245Ti with a Volvo engine bored and stroked to 2.6L, he uses an Art Carr race built AW-71, and he has Amsoil Superhift Synthetic ATF (ART) - which does easily meet Type F requirements.

I added an "t" to Dexron
I DON"T want to FILL it with the wrong fluid. I was asking about FLUSHING WITH F-TYPE and FILLING WITH DEXRON.

I honestly can't think of any way I could make my question CLEARER, again, I'm asking about FLUSHING WITH F-TYPE...... AND THEN FILLING WITH DEXRON

Thanks
Steve
(what is IOW?)
--
88 765 w/2stage boost & G-valve @ 14 psi

IOW = In other words

OK I did read the subject - and too be honest, it didn't make a lot of sense. Flush with the at least the same type of fluid you are going to fill with. I don't think the type of fluid for flushing will make a huge difference, in cleaning out old gunk. Some types/brands of fluid will mix with no problems others won't.

I think any semi-modern auto tranny would be best with the same variety of fluid - by flushing with F (and inevitably leaving some behind) then filling with Dexron, you'll have an experimental blend. Now, I don't think it will cause your tranny to self detonate, and it may even feel like it shifts better, but again it's masking a problem and may cause longer term problems.

Why did you add a "T" back into Dexron?

Adding "T" just haste/spelling

The reason I heard for flushing with F is that it will soften the band/clutch material giving crisper shifts. Apparently this has been done by someone, I wanted to make sure it wouldn't do irrepairable damage.
--
88 765 w/2stage boost & G-valve @ 14 psi

I don't think that the F flush will permeate the clutches for more than a few minutes before the mostly-Dexron fluid surrounds them. You will not remove all the F fluid, so as Pablo noted you will create an F-Dexron mix with slightly harsher shifting properties due to the differing friction modifiers in F. I also don't think this will harm the transmission, since the AW-70 series is fairly robust.