I have looked but cannot find the fill hole for the differential fluid on a FWD RX300. Anybody?

 

...but here is some info that may give you some ideas:

http://lexusmodz.netfirms.com/GS_DIY...iff/index.html

 

Thanks. I will try to look again (although I understand that info is for the GS).

 

The RX300 FWD (and also the AWD) have a 'Transaxle' : ie the Transmission and front differential are combined. I went thru this process recently.
There are TWO drain plugs underneath: one in a conventional horizontal plane, and one set vertically under a large cylindrical casting set on edge (probably the Planetary gear for the front diff).
(Gawd, a picture would be worth several thousand words here...)

The fill is thru the auto trans dipstick, just like a conventional automatic.

However, it doesn't normally need to be changed. Ever. And the auto trans dipstick is so marked.
If you do, remember to use Toyota T-4 fluid ONLY.....it was $11 / quart at my local Toyota dealer. I shudder to think what Lexus would charge.....

FYI On the AWD version, there is a Transfer case that DOES require fluid change (at 30K I think).

 

Use a synthetic gear lube...like AMSOIL or Mobile one. I couldn't find Mobile one in the exact oil weight but it was close. Mine has not leaked in the front or back.....as others on the board thought it could with a synthetic gear lube. I have checked every few thousand miles and the seals are holding fine. 85K on my RX

 

Almost forgot....It is very hard to fill the cases unless you can pump it in....very difficult to get the gear lube in since you cannot just pour it in.. There is no room above the case to hold the container. I had to use a long tube and slowly let it drain down in while wedging the container in a wheel well. It took an hour or two to fill but it worked. Make sure you fill it too and clean off the metal filings from the bottom bolt.

 

Just to clarify: You *are* talking about the 'Transfer Case' (AWD only) here, right ?
That does take SAE 85/90 Gear Lube, and as you say, is a bear to fill.

The original poster asked about the Front Differential, which is combined with the Auto transmission. Takes ATF.
Just don't want anyone to mix 'em up.....