AlphaTauri principal Franz Tost says the team have set Red Bull a deadline of September to confirm the spec of their 2021 gearbox.
The new 2021 regulations are set to change the ways in which teams can share parts, and under those alterations teams will no longer be able to take year-old designs.
AlphaTauri are developing a closer relationship with Red Bull Technologies and will continue to become more reliant on their sister team for parts.
But with the team now needing to run a current gearbox in 2021, the deadline has been set for September to fix the specification.
Speaking to Autosport, Tost said: “We will get also next year the front suspension, rear suspension, the gearbox and the hydraulics.
“But it will be decided in August/September whether Red Bull decides ‘okay this is the gearbox we run’ or whether they are still in the wind tunnel [to continue working on it].
“And then maybe we get the gearbox which is designed in September, because we will not wait or we cannot wait until November or December because then we don’t get a gearbox!”
Any alterations to the gearbox after September wouldn’t be major, but for Red Bull they could “become a big performance differential”.
“We will get the parts which are ready with the design in September,” he said.
“If Red Bull technologies still investigates for their car, then they could have something different. But it will not be completely different.
“Maybe the driveshaft is a little bit lower or higher, or the differential is lower/higher or further forward.
“This will only be a few millimeters but for a team like Red Bull Racing, it’s important because these small changes or many small changes can become a big performance differential.”