From memory the LT77 gearbox has reverse next to first gear, ie to the left then up. The R380 is below 5th, ie to the right then down. Easiest way to be sure but I'd bet your '93 has an LT77. I used Transmax in mine and it was fine, but then I've used standard auto trans fluid in my MGB V8 (LT77) and that was fine too. Again from memory the big hex nut is 36mm and a socket won't fit. Make sure you can open the fill BEFORE driving the oil.