The transaxle resting on some mounts in my workshop. It's 12 years old, from a 1983 Renault 30. Originally mated to a 140BHP 2.7 litre V6, it is incredibly over-engineered and will be able to cope with the 200+ BHP that SoulDriver's engine will eventually put through it with ease. Lotus use the same transaxle in their sports cars. The entire casing is manufactured from aluminium, making the whole unit very light (~30 kg).
This specimen is a 4-speed box, as it is better suited to the Rover powerplant than the 5-speed version. The clutch release arm and slave cylinder are missing. Although the casing looks corroded, the damage is superficial and can be easily blast-cleaned. (There's a picture of the reconditioned tranasaxle in this diary).
The term transaxle refers to a gearbox that also functions as an axle. There are two driveshafts, one leaving each side of the box and travelling directly to a wheel. The differential unit is housed inside the box, just behind the bellhousing and in front of the gears. The Renault 30 was a front-wheel drive vehicle, with the transaxle situated behind the engine and between the two front seats. The Countach is a mid-engined, rear-wheel drive design, so the transaxle sits between the two rear wheels right at the back of the car, with the engine between it and the passenger compartment.