Let Me Know if You Have Allison Transmission Fluid Questions

I have a 2003 DP I bought new with an Allison 3000 transmission and a CAT 3126E engine. The Allison came out of the Monaco factory with Transynd in it. The Allison manual said I should change the fluid at 5,000 miles including the filters, which I did. I was lead to believe that the fluid did not have to be changed again until 150,000 miles. I now have 38,000 miles on the rig. Should I change the fluid and filters now? Is Transynd in the Allison transmission not good for 150,000 miles? Thanks for your expertise.