Should I change my Transmission fluid? 7.3 diesel?

[MrHenrietta]

I have 40k miles on my ford reman transmission on my 99 Quigley SMB 7.3. Fluid has not been changed since install in 2010. FWIW I've never towed anything with it. Should I change the fluid?

[carringb]

Best stick to every 30,000 on the 7.3. I run way longer but the v10s don't eat them like the 7.3 does. Mostly because the v10 had a much smarter lockup a strategy that the diesel didn't get unless you run a programmer or lockup controller.

[VOODOO7.3]

...also replace the inline Magnefine filter while you're at it. They are often forgotten by DIY guys. It is 3/8" in/out hose sizes.