Pilot sleeve is a thin piece of metal that's inserted into the crankshaft to center the TH400 torque converter. The hole in the crank was factory drilled to accommodate a 727 converter which is bigger, so they used the sleeve to fill in the extra space.
The way to tell is to test fit the 727 converter to the motor. If it doesn't go all the way in, then the sleeve is in there.
It looks sort of like this, only it doesn't have a lip on it
"Usually found in a Jeep near Reiter, WA"
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