On my 1998 T100 (acquired at 307k...former work truck), I've already gone through one cleaning phase, currently in the first rinse phase. Cut the filter open and it was pretty dark...didn't strip it down and pull the material out so I'm not sure how much grit was in there. Looking through the oil fill port there was some grit in there originally. I scraped what I could out at first. During the rinse phase...the oil has darkened a lot from the original gold color to more like a cola color. I'll be replacing the oil filter around 500 miles into the cleaning phase. I'll be interested to see what's stuck on the filter at that stage.
I bought 8 bottles of Auto-RX and have already gone through 2 bottles...one fer the engine and the other fer the power steering and transmission. I've already drained the transmission through the cooler lines and refilled with new ATF. I used about 12 quarts of ATF before the lines ran with clean fluid. After taking it fer a quick spin and checking the level...it was about a quart high. So that got drained out...and it came out a little dirty from the torque converter fluid. I'll go through another purge next time.
I think I'll end up going through about 3 cleaning phases with this engine. I think it will be worth it in the long run...
