Transmission: ZF 4 HP-22 Automatic Transmission

For its time this transmission was very advanced. It was a four-speed automatic transmission in an era when this was highly unusual.

It also has a lock-up torque converter. This feature means that, at 60 mph or so, the automatic transmission starts to behave like a stick-shift transmission. This helps power and fuel economy, both.

This transmission is light yet very strong.

It is also very durable. It has a long life-time especially when serviced fairly regularly. Fortunately, it has several design features that make it easy to service.

BMW didn’t make this transmission; it was made by arguably the world’s leading manufacturer of automatic transmissions, a German company named ZF. This transmission was used in the flagship models of elite automakers such as Alfa Romeo, BMW, Jaguar, Land Rover, Maserati, Peugeot and Volvo.

This variant of the transmission contains no electronics and so it is extra simple to work on and trouble-shoot.


Engine: M20


Inspired by the classic BMW M30 six-cylinder engine, this is the “baby six” with a more modern design.

Small, light, durable and almost indestructible as long as it’s not allowed to overheat and as long as the timing belt is changed regularly.