I think they are called vespel sealing rings.not sure if that is the type of material.The rings that seem to do the least damage to the aluminum bore,coated or uncoated are the late 4L80E gapless type.The rings are made of some type of plastic material,I call them graphite but havent figured out what they are yet.
The rings that seem to do the least damage to the aluminum bore,coated or uncoated are the late 4L80E gapless type.The rings are made of some type of plastic material,I call them graphite but havent figured out what they are yet.