GS300, do you need to change rear differential oil?

[GSmk3]

 

Hi everyone,

Looking through the service document from Lexus, it doesn't seem like they recommend changing the rear differential oil for GS300, only inspecting at regular intervals for leakage (they do recommend changing for the ES, IS). Has anyone done this and is there much to gain?

Many thanks. 

[johnatg]

I can't imagine that the diff oil does not need changing. Normal operation of the diff grinds off tiny particles of metal from the gears (crownwheel and pinion) and also gradually degrades the oil. There will be a magnetic drain plug which catches much of the metal particles but gradually becomes less effective as the amount of what looks like sludge accumulates.

It's recommended for the IS at 25K intervals. Surely the ES, being front wheel drive, has the diff integrated with the gearbox, sharing transmission oil? Or are only recent ES models FWD?

Changing the diff oil can't do any harm - I use Lucas Gear oil 75W-90 in the diffs of RWD cars I look after. It's preventative maintenance! Optimally at 25K mile intervals.

Lexus service recommendations are a bit lacking - eg what about the brake sliders?

[westo3]

Interesting,  if this is a recommendation, as my diff oil was not changed by Lexus at 25k my be I should request this next service?

[Kijan]

Got same changed on big service in GS450h which would be every 30k km so matching roughly 25k miles. Surprised me why would they skip it in GS300, as this by logic should be changed and fully agree with John on that. 

[GSmk3]

 

I agree it makes sense (to change differential oil), just puzzled why Lexus would recommend it for some car and not others. The same for transmission oil, for Lexus GS it is in a sealed unit, so it is also not recommended to change. I'm not going to Lexus dealer anymore, the car is nearly 15 years old, but my local just do the standard basic stuff, so I'm trying to see what I should specifically ask them to do.