Hi guys/gals! ive searched the forums for related issues but they are a little too different to help with my issue.

I have a 98 rodeo S v6 4x4 a/t, 245k mi. When i take it on the freeway and am driving at 70mph or faster for a sustained amount of time, the check trans light flashes on. Now there are no physical symptoms happening, and the ecm does not go into backup mode. After i get to my destination, i unplug the battery and reset the ecm to clear the check trans light and it goes away, and stays away until the next time im going 70mph on the freeway.

Now, i had just bought the vehicle and the previous owner had a new tranny put in from another rodeo with only 60k miles on it.

I plan on buying a code reader, but i was wondering if any of you suspect anything going on, know whats happening or have had this same situation.

Many thanks!