A manual transmission foiled two would-be carjackers who allegedly kidnapped a man because they couldn't drive his SUV away from a Healdsburg park over the weekend, authorities said.

The suspects, two Oakland women, first allegedly robbed and assaulted the man's wife at Gibbs Park on Sunday before forcing the husband to drive them away from the scene, police said Monday.

The victim and her husband had gone to Gibbs Park to use the restroom, and while returning to their car, they saw a woman needing help, according to Healdsburg police.

When they tried to help her, however, she allegedly pulled out a handgun, demanded their personal belongings and vehicle, and then hit the wife in the head with the gun, police said.

When the suspect and an accomplice discovered they couldn't drive a vehicle with a clutch, they allegedly forced the husband at gunpoint and knifepoint into the SUV to drive them away.

Officers responded to the park and found the wife bleeding, and she was transported to a hospital for treatment.

After that, a countywide alert was issued for the victims' car, and a short time later, Petaluma police spotted it headed south on U.S. Highway 101. They pursued it with help from Marin County, San Rafael, and Sonoma County law enforcement agencies.

The husband was still driving the vehicle, and he ended the pursuit by driving off the road, police said.

After a short foot chase, both suspects were taken into custody. The husband wasn't injured and was reunited with his wife. A child who was with the suspects was found and was uninjured.

Davina Humphrey, 51, and Amina Vaden, 24, were both arrested on suspicion of crimes that include kidnapping, kidnapping during the commission of carjacking, robbery, child abuse, and assault with a firearm. They were being held at Sonoma County Jail, with bail set at $1.02 million.