I get this question quite frequently and I figured the best way to address it is to make a quick tech article on recommendations. When you get your brand new Tremec transmission you will see an orange ticket on the side that says "no fluid" which means the transmission ships dry to you. You will need to add fluid before you start driving the car.
What I recommend for a 200-300 mile break-in period (easy driving, no burnouts, flat shifts, no high RPM hard/quick shifts) basically just taking it easy for those miles. I recommend 2-3 heat cycles during this period, so basically put 40 miles on it, let the trans cool down overnight or whatever, and then bring it back to temp, then cool down again.
For this break-in period I recommend using any cheap, over the counter ATF Dex3 (Auto transmission fluid - Dexron-III) or compatible fluid. This should be a non-detergent fluid, you do not want it foaming up inside the transmission.
The transmission capacity is 3.75 quarts, so you will need 4 quarts of fluid to get you on the road.
IF you are on an upgraded trans with all carbon synchros (like my GR1000 units) then you do not want to run heavier fluid, the carbon synchros do not like the heavier weight fluid, i recommend just running a quality name brand ATF DEX3 fluid.
IF your transmission is not a OEM or "GR700" kit unit, then after the break-in period I recommend going to a slightly higher viscosity fluid (75W85), which will help protect the gears at high RPM, yet still allow the synchronizers to work as they should. The higher viscosity fluid will also help a little bit with rollover noise, as it helps take up that "gap" or space between the gear teeth.
I have had guys ask "why can't i just run shockproof or heavier weight oil"... and the reason to not go to a SUPER heavy fluid is this will make the synchronizers not move as freely and can cause a "notchy" feeling and will lead to grinds, which will shorten the life of the synchronizers.
The fluids I recommend, in the order of preference are as follows: Tremec MTF, Redline MT85, and Motul 75-85. If you are outside the USA or in a place where Tremec MTF is not available i recommend the Redline or Motul option.
I have the Tremec MTF fluid available for purchase on my website, and I try to keep it in stock. It is sold as a case of 4 quarts.
Hopefully this not only helps you, but also helps me as I will get the question less often!
- Break in period - 200 to 300 miles - use ATF DEX3
- For BUILT transmissions with all carbon synchros (GR1200) --- AFTER break-in use Royal Purple Sychromesh which seems to play well with the carbon synchros with no issues.
- For Stock transmissions or GR700 kit transmissions --- AFTER break-in use Tremec MTF, Redline MT85, Royal Purple Sychromesh, or Motul 75-85
- Capacity 3.75 quarts (T56 Magnum, Magnum-F, Magnum XL).
- Capacity 2.8 quarts (TKO / TKX / T5)