TRANSMISSION
Type 3/Type E/Type-9 Many of the early Pinto-powered Sierras came with the four-speed Type 3 or Type E gear boxes. The Type E is a better ’box to have, but you will probably be looking for a fifth gear when you are in the fast lane of the motorway. Some Sierras also came with the in Type-9 five-speed gearbox. If yours didn’t then it’s worth considering! Based on the Type E this is a reliable and relatively strong gearbox that fits into a Sierra with the right propshaft and gearbox bracket, and has a wealth of uprated parts available from the likes of Burton Power.
Mazda RX8 A cheaper alternative is to opt for a more up-to-date Mazda RX8 gearbox on an adapter plate from Butcher Race Engineering. If your car came with a Type-9 gearbox then this conversion is very straightforward.You can utilise the existing clutch, flywheel and starter motor.The boxes are stronger than a Type-9 and the same length so the selector pokes up in the right place.You have the option to go for a closer-ratio six-speed variant (above) which would be ideal in a high revving, naturallyaspirated build, or there is the five-speed ’box that is better suited for bigger torque from turbocharged engines. These come with a hydraulic slave cylinders so you will need to swap your pedal box for one with a hydraulic clutch pedal. Alternatively, you can buy a kit to convert the RX8 ’box to a cable clutch to retain the existing pedal. And lastly you will need to get your original prop shortened to suit.
Axle Sierras came with two options for their rear diffs — a 7 inch Tripod-style unit that has push in driveshafts and the more sought-after 7.5 inch Lobro unit that has external bolt flanges for the driveshafts. The internals of both are virtually the same and can cope with around 300 bhp without too much hassle. LSDs were available in all 4x4 Sierras and Granada’s 2.8/2.9 and 2-litre DOHC and of course the Cosworths. These can be hard to track down so you may have to look at buying a new unit from 3J Driveline to get both back wheels spinning.