using dexron most likely didnt cause that, mixing the 2 probably did. i use dexron in my 89 and 90, one without od, and one with, and neither have problems (although EVERYONE says my a518 should be dead 5 times over by now.) if in doubt though, go with atf.RamUinWI said:Do not put dexron in your tranny!!! I made that mistake. I blew a tranny line and i lost tranny fluid. The closest gas station had only dexron, I put it in just to get me home. Well, the tranny acted like a big bag of sh*t for the next couple days. It didn't go away until I did a tranny flush/filter change. PLEASE ONLY USE ATF+3 or higher!