The WC T5 must use ATF. A Stovebolt member was kind enough to reference his S10 Owner’s Manual and it said ATF for his NWC T5. You will NEVER go wrong with DEX/MERC ATF, no matter what T5 you have, NWC or WC. The ATF called for in the 88-92 Camaro T5 was DEXRON II which is no longer available. Other DEXRON ATF choices are too thin. I’m friends with the owner/operator of a reputable T5 transmission shop in Atlanta and he said to use DEX/MERC ATF. I’ve used synchromesh in a NWC T5 but switched to DEX/MERC. I like it better. I’ve had people tell me their T5 wouldn’t shift properly with gear oil.
