From wikipedia page, To adapt the BMW M52 engine to the Defender chassis, the engineers were able to utilize some of the parts from the recently developed BMW M51 diesel powered Range Rover 2.5 DSE. They used the clutch housing, clutch, flywheel, and slave cylinder from that vehicle to connect the engine to the R380 gearbox, but they had to produce a new clutch housing adaptor (bell housing) for the petrol M52 engine in the Defender. The unique clutch housing adaptor was necessary because the petrol M52 engine is tilted 10 degrees compared to the diesel M51 engine and it needed to be longer to match the input shaft of the R380 gearbox borrowed from the 300Tdi Defender. Due to the large diameter gearbox input shaft, the standard BMW pilot bearing could not be fitted, so a unique pilot bushing made of Oilite bronze was developed. It had an inside diameter of 7/8 inch with an outside diameter of 32 mm. A mixture of non-metric and metric specifications are common on Land Rovers. Other unique parts that were developed for the 2.8i were the air intake ducts both before and after the Donaldson FPG RadialSeal™ air cleaner,[17] engine mounts, radiator cowl, cooling hoses, fuel lines, clutch lines, air conditioning system, engine wiring, tachometer gauge, exhaust system, and a specially tuned Siemens MS41.0 DME with a Lucas 10AS alarm in place of the Drive Away Protection system (EWS) used on BMWs.[18] There were also major changes for the 1999 model year, which included updated instrumentation, different chassis and engine wiring, an updated cooling system with aluminum radiator, and an updated fuel system with new fuel tank.[18] The 1.667:1 gear ratio LT230 transfer box gave the vehicle a “rev happy” nature which delighted many off-road enthusiasts and made the vehicle particularly well suited for traversing a wide range of grueling terrain such as sand dunes.[19]The high gear ratio also helped the 2.8i sprint from 0-100 km/h in 9.3 seconds, making it the fastest production Defender ever made.[20]