I'm getting ready to change out the fluid in my tranny, t-case and diffs. I know how much fluid I'm to add back into the t-case and diffs, but the sm420 I have not a clue. This post: https://forum.ih8mud.com/showthread.php?t=50284&highlight=transfer+case+maintenance shows all the fluids and the amounts for an fj40, but sm420 was not stock in an fj40. I asked the guy at napa and he couldn't even find the sm420 on his 'puter. I've read that you can just fill 'er up until it's full, and I know I could in theory measure how much came out of it and add that same amount back in, but I'd like to know how much is *actually* supposed to go in there. I'm expecting to pick up some redline MT90 today or tomorrow to complete the job. Thanks.