I bought a 2000 4x4 blazer fri. everything was as it should be fluid wise, saturday it started slipping between 1-2 and 3-4 when on the throttle onto the highway or something. i checked the fluid and it was still ok, sunday as i was leaving the grocery store it wouldn't shift out of first. so i limped it the mile or two home at 20 mph. and checked the fluid again, this time it's way over the hot full and black. i'm hoping a fluid change and some lucas will help/solve. but i dont want to do that and find i need a new tranny after. anybody got any ideas as to cause or fix? i keep reading about governers and tv cables but i cant find much thats year specific