i was surfing around and came to the trd-japan site and found an lsd for our vehicle. i thought my rx300 had lsd already...anybody know if this is and upgrade to our lsd or is it an add on for those that don't have lsd...it says it's for the rear, isn't the rx essentiially a fwd until it senses some slippage? http://www.toyota-trd.com./en/suv/harrier.html so confused...

 

The LSD is for the rear and is only for AWD models b/c that is the only odel with a rear differential. The RX is a FWD based platform with a transaxle and sends power (on the AWD models) to the rear wheels. I think it's 50/50 all the time. There are others on this site that can explain the RX's AWD setup better than I can. Just watch out for wwest

 

As far as I know, lsd was an option for the 2000 and earlier awd models. It seems that in 2001, Lexus changed to electronic traction control and eliminated the lsd in the rear differential. As an 2000 year owner, I would prefer the simplicity and control the optional rear lsd gives. But given a choice, I would much rather that Lexus put the lsd in the FRONT differential rather than the rear. But I guess that might cause some "rear passing the front" problems. Anyhoo.

Also from what I understand, the Rx300 is predominately a FWD car. It has a viscous lsd seperating the front/reard differentials. As the front wheels start to slip, the lsd will start transfering power to the rear wheels(up to a predetermined point). My guess that this point is probably does not exceed 40%. If one of the REAR wheels start to slip, the rear viscous lsd(if so equipped as it was an option), will start transmitting power to the other rear wheel(again only up to about 30-40% of the available power can be transferred)

If you are curious to know if your 2000 and earlier rx300 has the optional rear lsd, call the Lexus customer service and tell them your vin #. They will go over the list of options listed for that vin. I know this because I bought mine used and wanted to know what the options on my car were. As it turns out, mine does indeed have the optional lsd installed .