Originally Posted By: dkryan
Critic,
While I'm certainly no expert at used oil or tranny fluid interpretation, I could figure out pretty readily that Toyota's claim that T-IV is good for 60k miles under "severe" conditions and 100k miles under "normal" service is bull.
With no towing and 60% highway miles on a regular basis, it wasn't like we were stressing the tranny. While the overall UOA was not bad, with only 20k on that fluid, it was clear it was not 60k fluid. Not without an inline filter and an additional cooler.
I trust the Amsoil ATF for a 50k run much more readily than I trust T-IV.
First, Toyota states that the fluid is good for 60k miles under severe service (towing), but does not specify a specific service interval for normal operating conditions. The instructions are to inspect the fluid at predetermined intervals and replace the fluid at the first sign of discoloration, sediment, or unusual odor. Scion’s website stated a while back (it may still) that the fluid is usually good for 60k miles or more.
Second, what criteria were you using to determine that Toyota’s recommendations were bull? Were the intervals simply out of your comfort zone? After all, fluid technology has improved significantly since the days of mandatory 24k ATF changes. As a comparison, we no longer change our oil every 3000 miles, but about every 5000 miles.
Third, again, what criteria were you using that led you to the conclusion of T-IV not being capable of 60k miles of service? If it was visual appearance, then the fluid should have been replaced per Toyota’s instructions, even if it had not reached 60k. If it was by UOA, then I do not believe that you hold the credentials to make an accurate conclusion.