We recommend that the fluid in a TREMEC Magnum, TKO or T-5 transmission should be changed after its initial 500 miles. The fluid should be changed every 30,000 miles after that. You can use a high-quality Dexron III fluid, or TREMEC HP-MTF™ manual transmission fluid. We developed HP-MTF to provide rugged protection while maintaining responsive shifting. It takes the guesswork out of which oil is correct for my TREMEC aftermarket transmission.
TREMEC HP-MTF transmission fluid with Mangum 6-speed transmission