With the advent of DIS, the dist is gone, but the gears and oil pump remain. This is sealed with an O-ring along. On the other side, is a pressureized gallery. In extreme cases, a quart every 100 miles is possible. More bad news.
Replacement requires cylinder head removal.
And the final think on the subject of maintaince, the transmission. I have put a few hundred passes on my 4T60E on the dragstrip. I race SCCA autocross regularly. I drive at high speeds. I live to beat someone from a stoplight or leave them halfway around the on-ramp.