Quote:
Originally Posted by amacman
hi, i drive a 2002 X5 4.4i sport auto permanent 4wd , the 2004 onwards have xdrive , this means they usually only drive the rear wheels so that you feel as though driving a rear wheel drive . the transfer case has a clutch pack to engage also the front wheel drive or send power in variable ratios to front or rear .
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Not correct. Both xDrive and non xDrive models have a nominal 40%/60% front/rear drive bias (non xDrive is actually 38%/62%) on a high-traction surface. The difference is that the non xDrive has an open planetary style centre diff whereas xDrive has an electronic multi-plate clutch pack that can proportion the drive front to back according to the available traction and driving conditions. In a low traction environment, non xDrive only has its electronic traction control to help get the drive to where it can be best used whereas xDrive has both the centre clutch pack and ETC. With xDrive, it's only under extreme conditions that all the drive is directed towards the rear wheels.