type"F" or dex/merc

[mat in tn]

I'm rebuilding my 81 c6 from the f250 camper special. when I picked up the parts at the warehouse I asked for a case of type f and she looked at me as if to say "what".  I explained so she called "upstairs" to which she got told case of dex/merc. I bought a case as I use it on aod's regularly and I just spent a case flushing one. but I'm asking for opinions of the experienced. on a fresh rebuild with all new seals, steels and frictions. is there any real reason not to use dex/merc? absent a locking mechanism, the c6 is hydraulic 100% meaning constant generation of heat from the TC along with general friction and warming from the engine  

[85lebaront2]

Mat, I will throw another out there, Chrysler ATF+4 or there is another number for it, I believe it is 7476. It is a synthetic like Dexron, but has a friction additive like type F. It was released to help keep the A604 or as it is now designated 41TE transaxles alive. These have no capability to adjust line pressure according to load and were know to burn up under hard use, especially in the minivans with the 3.8L V6.

I do remember my surprise when I found Darth's C6 called for Dexron rather than type F.

[mat in tn]

thanks. this is about as expected.   I'm certainly up for using dex/merc as I'm using a bit of it already. I know "following the rules" is a safer way to go generally and I grew up "knowing" type f for fords and dextron for Chevy's. but never really knew the specifics of why. almost everything I have built for 20 years or more has used dextron, even manuals.