I just changed the fluid in my 92 Wrangler using Redline MT-90 about 2 weeks ago. Reviews by others and the company's claims made me go with the Redline; I have only had the Jeep for a few months and don't know what was in there previously. I really haven't noticed much difference; the transmission shifting is still a little notchy but it seems a bit less noisy now.
It's a bit thick. The factory part number for fluid is a 10w30 motor oil. MT90 is for transmissions that calls for 75w90, the wrangler's owners manual is a misprint. MTL is a 70w80 equivalent to 30 weight but designed especially for manual transmissions. I had 75w90 in mine and it shifted like hammered $hit. Put 30 weight in it and it's much better. But I'm still gonna go with MTL next time.
