Sebastian Vettel will not have to incur a penalty for replacing a gearbox at this weekend's Japanese Grand Prix.

After Ferrari's horror outing in Malaysia last week, Vettel headed to Suzuka under a cloud due to his bizarre post-race crash with Lance Stroll.

The team had sent the German driver's gearbox back to Maranello, fearing that a replacement would cost Vettel five penalty places on the grid this Sunday.

However, Ferrari have said the gearbox is in fact "still available" to use in Japan.

"Only the outer casing of the gearbox was damaged," a Ferrari source told GMM. "That can be replaced without a penalty.

"It's our best news for weeks."

Another piece of good news for Ferrari is that the carbon connections for the turbo units were also sent back to Maranello for checks, following two near-identical failures that cost both Vettel and Kimi Raikkonen in Malaysia.

The parts have reportedly been reinforced for Japan, with the changes also not incurring penalties because they were completed purely for reliability.