whitels

I may be wrong but upon reading the manual, my understanding is the differential uses for >(0 deg F) a 85W-90 oil. However, I cannot find a filler plug for the darn thing. Which makes me wonder, does it also use or share the same fluid type T-IV with the neighboring transmission?

SharpLS-96

No, not at all. Uses a "GL-5" rated Gear Lube Oil" not Toyota T-IV- ATF. These are two totally different fluids that serve two totally different purposes. Filler plug is on the top of the actual differential housing your draining not under the hood near the engine if that's what you were referring to or thought.

See if this link helps in finding the fill plug. Scroll down to where "LexusTech" explains how to change it.
https://www.clublexus.com/forums/sho...rx300+gear+oil

whitels

Thanks for the link. I read it but it describes the AWD RX300 which has a transfer case. The filler plug is near the passenger side which, in contrast to the FWD, is closer to the driver side. Regardless, I will try to use the technique mentioned in "feeling" for the filler plug

VVT-i

If you drain the fluid from the diff and transmission(not the transfercase) on the FWD RX300, then you can fill it up from the trans dip stick tube. It takes about 4 qts of type T trans fluid for a drain and fill transmission pan and diff.

whitels

VVT-i,

So you're also saying that the diff and tranny uses the same type T-IV oil and actually share the same fluid? The FWD has no transfer case, right?

VVT-i

Correct, the FWD RX300 share the same type T fluid and can be fill through the transmission dip stick.