[adam83]

Getting ready to do fluid and filter change on a 71 Torino with a C6 trans. The car is not numbers matching and has a 9" and a C6 and 351c.

I'm not sure what year the trans is, and I'm not sure what fluid is currently in it. most likely it's type F or Dex/Merc

Is there a way to visually tell the difference between the 2? Smell perhaps? Viscosity? Should I just drain a little bit and compare it to a couple of jars, 1 with f and 1 with DEX III?

 

[ExcellenceAuto]

I'm pretty sure they are compatible with each other. Back in high school (80s) we would put Type F in everything. We thought it would make the tranny shift harder, kinda like B&M Trick Shift.
Now I have done some silly things in my life, especially back then and this is probably one of them. So you might want to get a second opinion!
Do they even sell Type F anymore?

 

[BogiesAnnex1]

I run Type F in my built 700R4. It is still the racers go to automatic trans oil. You can get a synthetic in 3 different viscosities from 30 to 20 to 0W-8 from ATI to even a Type F under the Super Tech label at Walmart. My 700R4 uses Raybestos Z-Pac clutches and Kevlar band

Modern ATF is formulated for PWM controlled transmissions so it has some additives that allow a bit of slip in the clutches and bands to soften the shifts.

Bogie

 

[chasracer]

Dex is normally going to be on the "clearer" side whereas Type F is always a nice red color if its in good shape. A lot of us that drag race are switching over to Allison Transynd Synthetic. It's pricey at about $50 a gallon but the stuff just doesn't give up on you.

 

[BadWally]

While some of you may laugh or think I am nuts, but for years I have been using tractor fluid designed for wet clutches in Combines and other farm equipment. It is clear trans fluid and It sells 5 gallons for about $38.00. I was using this in my farm equipment for years and started reading the specs. I used it first in a turbo 350 years ago (at least 10 years) with no problems. I think it actually shifts better. I now use it in everything and it works great. Hey if it good enough for a $250 thousand dollar Combine, i think it's fine for my transmission. Big tractors and combines operate in conditions of high heat, dirt and dust that a older auto transmission is rarely subjected to. it works for me,