For quite some time now BMW has been relying rather heavily on one particular part for the entirety of the model line-up – The brilliant 8-speed gearbox. The ZF produced transmission was used in everything from the 1 Series to the X7, otherwise also known as the ZF 8HP. This torque-converter automatic gearbox is so popular because of a couple of very important reasons and who better to explain them all than Jason from Engineering Explained”?
In his most recent upload, he happened to drive the brand new BMW X7 and, since that car is fitted with different variations of the 8HP gearbox, he probably got the idea to explain why this is the best automatic cog-swapper in the world. A number of factors contribute to this bold claim. The main reason why this gearbox is so loved has a lot to do with the way it changes gears, the upshifts and downshifts being silky smooth.
It may seem irrelevant today but before the 8HP came out, the automotive industry and the customers/owners were used to a different kind of shifting experience from automatics. Furthermore, the ZF unit is also more efficient while also coming close to dual-clutch units in terms of speed. Thus, a number of car makers are using these units, from BMW – of course – to Dodge, Alfa Romeo, Jaguar, Audi and even Rolls-Royce.
This is such a popular unit that ZF built 3.5 million units last year alone, just to keep up with demand. The latest iterations are found in high-performance cars like the F90 M5, where shifts are so fast, you could easily mistake this torque-converter unit with a DCT gearbox. Jason goes through a lot of details in the video below, so you might want to watch the whole things to learn a couple new things.