Williams could run Mercedes gearboxes next season as they look for a closer collaboration with their engine supplier.
Next year, Williams could add their name to the list.
“We are in discussions about doing that,” Mercedes team boss Toto Wolff told the official F1 website.
“They are an engine client of ours. It’s not a huge thing to increase that to a gearbox.
“Nothing is signed, nothing is done and we need to decide in the next few weeks because the chassis design is at an advanced stage for Williams, so we’ll see how that pans out.”
This has raised questions about how close Williams are willing to tie themselves to Mercedes.
The team has insisted several times this year that they want to remain independent, however, tech boss Paddy Lowe says they have their “eyes open” to collaborating with Mercedes.
He added: “Formula 1 is changing. Force India were one of the early ones to abandon the full constructor definition that teams had historically followed of essentially making everything except an engine.
“We’ve seen more and more teams adopting gearboxes from elsewhere. Now we have the Haas model where you adopt everything that is not listed.
“We have our eyes open to all of those possibilities because we owe it to ourselves. You’ve got to move with the times and do the best thing for the performance of the team.
“But having said that, Williams has a strong culture of being an independent, being a constructor, not only in the parts we are responsible for but also we are making them in-house.
“We have a capacity of manufacturing on our own site and we’ve prided ourselves on that. I don’t see us moving drastically away from that. But we remain open.”
Williams are currently bottom of the championship with just four points in 11 grands prix.