The incident was reported on southbound I-280 near Alemany Boulevard at 5:13 p.m., according to the CHP.
The truck was hanging over the edge and debris and possibly oil from the big-rig had fallen onto south and northbound lanes on Highway 101 below, CHP Officer Peter Van Eckhardt said.
Both directions of traffic on Highway 101 were shut down, Eckhardt said.
The cab of the truck, which reportedly was hanging about 40 feet over the roadway, had been pulled back by 6:10 p.m. and after a brief inspection, Highway 101 was reopened at about 6:20 p.m., the CHP said.
No injuries were reported.