I am familiar with the AWD system of the BMW X5 but was curious as to how the AWD system works in the RX330.

Any info is much appreciated.

 

Here's a start to getting you some info on the AWD system of the 2004 RX330. I'm referencing the 2004 Lexus RX330 New Car Features book (part number NCF241U). I purchased it from the Lexus parts dept.

Page CH-36: 4WD System Description
"... a full time 4WD system that constantly distributes torque at a ratio of 50:50 to the front and rear axles."
"... this system, which has adopted front and center differentials with bevel gears, employs TRAC control in order to ensure proper drive when a wheel slips, without the use of an LSD (Limited Slip Differential) mechanism in the center differential..."

The reference book shows diagrams of the 2004 system vs. the 2003 RX300 AWD. The '03 had a center differential w/ a viscous coupling LSD. The '04 has bevel gears instead of the viscous coupling LSD. The rear differential is still a "conventional" type with 2 pinion gears. The transfer case has it's own lubrication system (~1 qt of SAE 85W-90), while the front & center differentials are lubricated by the transmission ATF.

As you probably know, the RX330 employs a full-time AWD system. As mentioned above, TRAC control is required, so you'll find that the TRAC-OFF override button (normally located beneath the steering wheel, at about knee level) is not included on the AWD models (it is still available on the FWD models).

Let me know if you need more info, this book is pretty insightful at a "systems" level.

- HiTechRX

 

Thanks kindly for the info. Much appreciated.