It is very unlikely that a 2001 has Transynd, original factory fill was Dexron III. If you want to change to Transynd, the 1st oil change after putting in Transynd and the Gold Filter is 12 months/25,000 miles. After the 2nd fill and filter change, Transynd is good for 4 years/150,000 miles with a filter change at 2 years/75,000 miles. Allison dealers charge about $100-$150 more for a Transynd fill than Dexron III, but that difference is made up quickly by not having to change oil again in a year.