Engine transplants - Changing FDs and speedo drive ratios.

What they don’t tell you in the manual! Terminology - FD - Final Drive (diff ratio) What they don’t tell you in the manual! If you’ve decided the FD fitted isn’t what you want, changing the FD is possible without separating the engine from the gearbox. Removing the diff case will allow you access to the diff assembly to change the crown-wheel, and access to the gear-change linkage. Use a manual for crown-wheel replacement. While you’re in there it would be just as well to replace the thrust washers and diff-pin as these are the source of many a gearbox problem. Particularly for up-rated engines where fitment for the competition diff-pin is highly recommended. Once again, follow the manual here. Now the bit they don’t tell you how to do... Rod-change types - Removal of the speedo drive housing gives access to the pinion retaining nut (1.5”AF socket needed and a long bar). To be able to undo the pinion nut (torqued up to 150lb ft !!) you need to engage two gears - 2nd and 4th - t