T-5 fluid capacity

[MVG•GT93]

I know this thread is over 5 years old but I'm trying to decide what I want to fill my trans with. I was looking on american muscle at the Royal Purple synchromax and I read the reviews, only one review was bad. And after reading this thread I can't decide if I should use 10 w30, ATF, or synchromax.

 

[Tim Steel]

I know this thread is over 5 years old but I'm trying to decide what I want to fill my trans with. I was looking on american muscle at the Royal Purple synchromax and I read the reviews, only one review was bad. And after reading this thread I can't decide if I should use 10 w30, ATF, or synchromax.

OK check this out: I'm the one-owner of my 1991 mustang GT with the t-5. My t-5 is still the original today and running flawlessly. All I've ever done to it is to replace the aluminum Throwout Bearing Retainer with a steel one (~$60) and replace the ATF every 50,000 miles. It now has over 270,000 miles on the same transmission and I still drive it today. No .
I've only used mercon ATF /mercon V or its equivalent. You have to put in 5.6 pints or up to the fill line. See its original owners manual in this post.