So I just learned that my car has rear differential fluid (from you all here). It is a 2013 450h with 63k miles on it. I bought it CPO in 2019 with 55k on it and it was serviced 4 times at Lexus doing the 65, 70, and 75k services. So, of course my question is, how often should this fluid be changed and if the car had been serviced at a Lexus dealership since new (based on the records on Lexus drivers), do you all think it has been changed, and how do I check the fluid level/condition. Sorry for asking such basic questions. First time I have had a RWD car since a 1976 Buick Regal, way back in the late 80’s. Wow, I am getting old. Thanks all.

 

For US spec models, rear differential fluid change isn't recommended until hitting the 150k mark. For most people, thats the entire length of their ownership on the original fluid. I doubt its been changed by the dealership at those service intervals you mentioned.

See this helpful thread: https://www.clublexus.com/forums/gs-...al-change.html

I had mine changed at 47k miles by my personal mechanic but don't recall feeling any difference in drivability - the fluid was dirty at that point though. I have an AWD with 64k miles currently and haven't done the front differential fluid (but i'm not planning on doing so).

 

It's a contentious topic on this site, some say never. My 2 cents, if you plan on keeping the vehicle past it's "lifetime", let's say 12-15 years, 150K miles, best to do this at 60K. Otherwise, the people preaching never to do this (as well as trans) on this site have a valid point. It's cheap insurance that may help prevent a future expense way down the road.

 

My GS250 here in Europe has rear diff fluid interval of 20k miles (!!!) which is absurd on the low side.
but it’s cheap and very simple to do so why the heck not?

 

Thanks everyone for your quick response. So the answer is the rear differential is like the transmission fluid. It is lifetime no change by Lexus recommendation in USA, but there are people on both sides of the spectrum. I was seeing some comments that it is supposed to be changed every 30 to 50k miles. Which is 2 to 5 years for most people driving. My low miles per year and I am going to be hard pressed to hit 100k before 2030….

 

In my opinion it’s absurd to say that any oil is “lifetime”.
Everything wears, including oil. But wears at different rates.

Diff fluid is a $20 job if you do it yourself which anybody with a brain can do.

 

Unless it is leaking Lexus doesn't recommend touching it.That's why in the manual it just says to inspect. The diff is a simple drain and fill compared to the transmission. I'm at 119k miles on my 2013 450h and haven't touched it, zero issues. Everybody has their own opinions regardless of what Lexus says. The opinions on this forum are all experts that designed/manufactured the car.

 

As you can see opinions differ greatly. Change it or not is a personal preference. The US manual says it is lifetime and the rest of the world says different. I don't think the trans or the fluid is different.

I did my transmission, front and rear differentials last year mostly because I was bored and was playing with my new lift. If you were going to change the rear diff fluid, I would change it with a good synthetic for the extra protection. It will be dirty but most of that is break-in material and it isn't hurting the differential. A rear differential is one of the least troublesome parts of any car unless you have racing slicks and over 500HP.

I would consider the transmission fluid, also spec'd as lifetime, the more important fluid to change. It is a very complex piece of machinery with 1,000s of parts and some of them do wear. If you do a drain and refill without changing the filter, you will introduce enough new fluid to protect anything in the trans for another 70K miles, or whatever your change interval. I used the with no issues so far in 2,000 miles.

 

20k miles diff fluid change according to Lexus’ sold in Europe.
Lifetime = US
20k miles = Europe (atleast in my service manualk)

Same with trans fluid.
60k miles (if towing). Why change if towing and lifetime if you don’t? How much towing does one has to do to fulfill the “if towing” comment?

 

Service that car. Fluids are the lifeblood. I recently serviced our 2013 GS350 F Sport. I used a cheapie garder sprayer to put the Red Line 75w85 fluid back in. Easy peasey.

 

On another note, always take the fill plug out first. If it doesn't come out and you drain it, it is tough to fill it back up.

 

I do somewhat like tinkering with cars just for the knowledge that I can do it, and the self satisfaction that no one will be as careful with the car as I am. However, I am going to wait on this and the transmission until I hit like 75k miles or so. That should take about three years so it gives me plenty of time to either sell the car, or retire, and have loads of time to do this stuff. Possibly with at least a floor lift jack thing which gets the car somewhat off the ground. It is really getting harder to get under the cars, especially this car. I can’t imagine lowering the car and then having to jack it up every more. Good discussion though. I like different opinions.

 

I'm not a professional mechanic, nor am I certified with anything, but rather simply a guy that's been working on car's for myself since the early '80s. You could consider me somewhere near the same level as Mona Lisa Vito in My cousin Vinny. Just throwing in my 2 cents FWIW.

With that, I also side with changing any differential fluid every 60K even if not considered necessary as well as changing trans fluid periodically (although I don't remember the mileage-interval because I have it written down on a pad in the glove box outside). I do also strongly side with the opinion of NOT performing a trans flush. A simple drain and fill to level is all I'd do. I'd also take into consideration how many miles the trans and diffs are covered for and maybe time my fluid changes with that. For example, if my warranty covers the trans to, say, 50K miles, I'd change the fluid at that point.

Draining - Good, Flush - Bad.

My neighbor is among 1 of 3 people I know who ended up exactly as Scotty Kilmer predicted. He had 130K on his Honda buggy wagon, had a full flush performed at the recommendation of a garage mechanic, and the trans started getting sloppier and sloppier, and finally completely soiled itself by the time it hit 150K. Went completely bleeeaarrgghhh.... Wouldn't even budge anymore.

 

'70 Buick GS Stage 1? NOW we're talkin' cars!

 

What? That old thing! LOL. I've owned it for going on 42 years. It was my college transportation in the early 80s.

I make the joke that all my cars are GS's. I'm pretty sure they are, in order of fastest, are the 1970, 2013 and 1971 being slowest.

This all my GS cars.

Buick GS, 71 on left, 70 on right.

Lexus GS 2013