Does a clio 1.5dci gearbox fit a clio 172?

No, a Clio 1.5 dCi gearbox is not compatible with a Clio 172. The Clio 172 features a different engine and transmission design, as it is part of the sportier RenaultSport lineup. The 1.5 dCi is a diesel engine with a gearbox tailored for that configuration, while the Clio 172 uses a gearbox designed for its higher-performance petrol engine. Thus, attempting to fit one in place of the other would not work without significant modifications.