Rx 300 Rear Diff - Oil Change

Forbesy · October 31, 2014

Hi All - Thought I'd give a few pics of my latest fixup escapades on the new ride.. 55-reg with 75k miles. This time, the rear diff oil change.

Took about 45 mins, with the majority of that spend trying to undo the filler plug ! Easy job though and well worth doing if you're unsure of history, as I am !

Parts and tools:

1 litre GL5 oil (I went for fully syn at around £15)

10mm allen key

oil squirting device (I got the one below from Machine Mart at £9)

Fill plug green, drain plug red - Hint: Always undo the fill plug first ! You don't want to be stuck with a drained diff you can't refill ;) On mine, the drain plug was easy enough, but the fill plug took a considerable amount of Plusgas, then 'freeze & release' spray before it would give way..

I drove around for about 15 minutes to get some heat into things before draining.

Drain away... I only caught this pic at the end of draining and the oil looks pretty clean, but the first bit that came out was black - The whole lot also stank like rotten eggs.... Please, if you do this - Wear gloves ! To be fair, even the new oil had a bit of a funky smell to it, so I don't think this is unexpected.

Magnetic drain plug certainly does its job !

Before:

and after:

Easy from here - replace drain plug (mine didn't have a washer on it) and refill diff until oil comes out of the fill hole - The Machine Mart pump took 2 fills to get this done (great tool, took about 3 mins). Replace filler plug - mine did have a washer on it, which I just cleaned up and reused, but no leaks as yet !

I think the schedule on this job is @60k, so I'm pretty sure mine wasn't done - But glad it is now !

Boxbrownie · October 31, 2014

The oil should look clean as there are no carbon deposits from combustion gases or friction plate residue from transmission.......I guess the egg the bored Japanese worker put in on assembly finally went "off" :winky:

japanesebob · October 31, 2014

hmm...I was worried about the underneath of my 03 rx300 being rusty but it looks just the same as yours. A mechanic told me that the underneath a of Janese cars always look 'orrible, perhaps he was right.

Good set of pictures, I think I'll have a bash at this myself. Did you just scrabble underneath or put it on some sort of axle stands?

ColinBarber · October 31, 2014

hmm...I was worried about the underneath of my 03 rx300 being rusty but it looks just the same as yours. A mechanic told me that the underneath a of Janese cars always look 'orrible, perhaps he was right.

Maybe the Japanese cars always looks bad because all the parts are still original, unlike some others where half the bits have been replaced ;)

That said the series II RX always seems particularly bad, they really skimped on the under chassis protection on this model.

Forbesy · October 31, 2014

Yeah, must admit to being a bit concerned about the chassis rust although it doesn't seem structurally troublesome as yet, another job on the list is to spend some time with a wire brush and some POR15 paint... can't hurt !

For the diff I put it on some ramps, but reckon there's enough room to shimmy under there without anyway..

Boxbrownie · November 1, 2014

The subject of rusty bits dangling below has been on here before, it does appear it is common with the RX (maybe all Lexus/Japanese cars) but it always seems to be a superficial rust on the surface of the chassis, it looks like structures such as steel suspension arms and brackets etc get the worst of it. And yes a dousing of wax or some such would do no harm.