So whenever I read a thread or post about build T45's or atleast rebuilt ones from all kinds of different builders (The T45 Source, Hanlon, Astro, etc.) they all recommend Mercon 5. It's funny because stock our cars take Merc 3. Now I was thinking maybe they are recommending the more slippery stuff since they are using carbon fiber lined synchro's. Some people say run whatever the builder recommends, others say that our transmissions were designed for Merc III so use that. I used Merc V since that is what my builder recommended. I had that in there for 6,000 miles or so. Lately the shifting hasn't felt as good so I figured I'd drain the fluid and see what it looked like, and just put some fresh stuff in. My old fluid was already fairly dark and has lots of tiny shiny pieces in it. Granted that is with lots and lots of redline shifts and not being easy on the car at all though. I ended up trying out the Mercon III and it feels much better than it ever did with the Mercon V! So I'm going to run Mercon III for about the same mileage and drain the fluid to see what it looks like. I know that it definitely feels better to shift though.
So I was wondering if anyone else has tried Merc III instead of Merc V and what your findings were. Also, I would encourage people with Merc V to switch to Merc III in their aftermarket built transmissions and report the results.
So I was wondering if anyone else has tried Merc III instead of Merc V and what your findings were. Also, I would encourage people with Merc V to switch to Merc III in their aftermarket built transmissions and report the results.