NickSP

I've changed the transmission fluid and brake fluid but what do I need in order of maintenance with respect to AWD? Thanks.

Clutchless

I am pretty sure you have a rear differential that takes Toyota WS ATF. Check your owners manual. Also try searching differential on this forum.

This video is for the 2014 Highlander hybrid AWD but I suspect the RX450h is about the same.

NickSP

OK thanks. This is the same fluid as the Transmission I guess. I will look for differential.

tempestv8

I have not bothered to change out the rear differential, only the transmission fluid in the front. I would expect that the rear differential, which uses the same Toyota WS fluid as the front, will remain in great condition even after a very long period of time as it is not subjected to much heat at all. So I might actually treat it like "lifetime fluid". But not the front transmission, which I would replace periodically, as that fluid can get that darkened "burnt" look after a while.

NickSP

I don't do any offroading or towing. Guess I'll follow your advice and treat that as lifetime also.

tempestv8

It's been a year since my previous post.

I only just noticed from the owners manual that the hybrid rear differential (RX450h) uses 1.8 litres of Toyota Genuine WS fluid whereas the rear differential of the RX350 uses a completely different quantity and type of fluid.
RX350 uses 0.5 litre of 75W-85 GL-5 gear oil.

I guess the difference is that the RX350 has a crown and pinion type of differential whereas the RX450h has an electric motor with presumably very different style of differential, and the bigger volume of fluid will help disperse the heat from the electric motor.

Given the vehicle has hardly been driven in the last 12 months, I'm going to leave it till maybe next year.

salimshah

I was surprised to find that the CVT and the rears diff needs ATF. I had always associated ATF with torque convertor and valve operation through solenoids.

Salim

sagan

Most CVT's use ATF no? The rear is driven by the electric motor only so I'm guessing it really behaves (and is) more of a transaxle.

The rear is super easy to change, way easier than the front. No reason not to change it, takes all of 5 minutes.