Getting back to the original question, it depends upon the age of the engine and the sludge level. ATF is very detergent as you know and will clean out sludge pretty well. You wouldn't necessarily want to add it on a regular basis by the quart. More likely, add a cup full about 100 miles before changing oil if you just feel the engine is very dirty. If you have a sludging issue, be certain that the pvc system is free and open first and then add 2-3 cups of ATF to the oil, and then change the oil filter every 3-400 miles, adding oil and ATF each time. The ATF will free up a lot of crap so go slowly and change the filter often. No, this is not something that TRD is going to find documented in the Toyota service manual, but it seems to work over the last 50 years or so, so it likely will do no harm and can potentially eliminate a sludge problem.