Originally Posted by BNR34

Just replaced the rear differential fluid myself on both my 05' LS430 and 06' SC430, here are my observations that I like to share with you guys.

On my LS430, is been 30k miles since the fluid was changed, so I decided to change it. I had the dealer did it last time because I was busy and the car happened to be at the dealer.

The procedure is very simple, is nothing to it, drain the fluid by removing the drain plug and fill up the case with the fill hole. I put in roughly 1.8 Qts of Valvoline Synpower Full synthetic gear oil 75-90W.

The observations is, the fluid is still very clean, I can hardly tell it got any dirtier at all. My theory is I drive this car very gently, I rarely floor it, it is mostly cruise at the speed limit.

I am continue to be unimpressed with the quality of Lexus dealer's service work. My theory is still correct, the only way to have anything done perfectly, is doing it yourself. The fill plug is half stripped and there are 2 washers on both the drain and fill plug, which means the guy put a new washer on without removing the old washer Luckily there is no leak. He did get the fluid level correct and the plugs are on with the correct amount of tightness. But still when I pay their ridiculous service charges, I expect the work to be 100% perfect. Nope, far from it, the typical rush it thru as fast as possible type of work I am so glad I did it myself this time. And my service advisor kept bugging me about letting them service my car. I be sure to let him know the crappy job they did on it and that is why I work on my car myself as much as I can

On the SC430, the thing I didn't like was both the plugs was on super tight, is like they tighten it with a huge breaker bar At least there is only one washer on each plug. The other curious thing is the fluid is starting to look unclear, and it had only been 15k miles on these fluid. It makes me wonder if the dealer really changed the fluid like they said they did Since the fluid on my LS is still very clear at 30k miles. But I do drive the SC a lot harder then my LS, so that might explain the difference in the fluid dirtiness.

That's it, oh and the LS got a lot more room to work with then the SC, both differential looks identical as expected

Originally Posted by sorka

I replaced the diff fluid on my SC400 for the first time at 180K miles. It came out light honey color...i.e. the same color it was when it went in. I realized I wasted my time.