Tractor's I'm using are:
1965 Case 530 four cylinder diesel.
1965 Case 730 four cylinder diesel.
It's the 530 that I poured the ATF in. Like I said, one quart to five gallons of fuel more or less, (I wasn't exact in my measurements). I noticed no effects either good or bad. The ATF I used was some very old stuff I found in the back of my Dad's barn. Cardboard "cans" with metal tops no less. Two gallons of Dextron II "Sears" brand. Therefore, while it was "old" it had never been in a transmission so no wear metals or "trash." However, I'm going to have some "used" stuff pretty soon as I plan on changing ATF on my truck, my daughter's car and my wife's car in about two weeks. If what you guys say is true, I should be able to "boost" the mixture to 10 percent.
As a side note - I have also burned Marvel's Mystery Oil, (one quart to five gallons) in this same tractor. Tractor seems to run better, smoother and stronger when I use the MMO. Could be because the solvents are more "explosive." I don't know. By the way, I am using number 2 off road diesel.
Shannow - Regarding cost of fuel verses motor oil - never thought of that - the local dollar store is clearing out their 30 weight ND motor oil for 50 cents a quart. That's two bucks a gallon. Right now in these parts, (Central Florida), I'm paying $2.35 for off road diesel for my tractors. Hummmmm - looks like a trip to the dollar store today!
While I'm rambling, I've tried the rope method of filtering my used oil for this very purpose. The oil climbs the rope to the top of the loop and then stops. I've let it sit there for months on end and it will not go any farther. What am I doing wrong?