BNR34

iTrader: (1)

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

tfeni52355

Thanks for the feedback. With 35K miles on our SC I will be changing it soon.

SteadyEddy

iTrader: (1)

Some mechanics don't realize that tight is tight and too tight is broke. A torque what? Thanks for the heads up, I think I'll look into that on the SC also. Can't hurt.

JerryB

Hi Guys,

Re: Some mechanics don't realize that tight is tight and too tight is broke.

IMO some mechanics, in order to make money at the flat rate, will use pneumatic impact wrenches. They run those things until nothing is moving; and they NEVER adjust them.

Just because you are at a Lexus dealership does not mean that you get a good mechanic. That is why I use an independent shop; 18 years with him now.

Jerry Baumchen

BNR34

iTrader: (1)

Well said Jerry, agreed 100%.

I only use the dealer for free warranty claim, they replaced the diff. fluid last time just because the car was there already. I do everything myself when I can, the only job I don't do is timing belt replacement.

You are right, the work is only as good as the mechanic himself, and being a dealer doesn't mean anything. I am just amazed how many people still believe the dealer provide the best quality work for their car

JerryB

Hi BNR,

Re: I am just amazed how many people still believe the dealer provide the best quality work for their car

+1,000 That is why they are called the 'stealer.'

I live in Beaverton, OR ( a suburb of Portland ) and there is one & only one dealer in this area ( they are only ~ 3 miles from my house ), but they just will not do anything in the way of a 'good deal.' They had some 'take-off' wheels that I was interested in but their pricing was simply outrageous. I took a pass on the wheels.

Jerry Baumchen

Harold57

I guess those of us in the major cities with multiple dealerships are blessed since the threat of competition works wonders towards customer service and quality. To my knowledge, the dealers in our area do quality work, doesn't come cheap but you can generally trust it.

antigeek

I agree, Harold. I started reading this thread and started thinking we were cursed, as it's hard (for me) to tell if an aftermarket shop here in Big D does a better job. I do think that with the options we have, it falls back to individual experience. Otherwise, everyone in Texas would have a Ford / Chevy / Dodge truck (as they all say they're the best).

BNR34

iTrader: (1)

Since it is the only dealer close by you, they can get away with stealing

scdroptop

iTrader: (1)

I posted last year sometime about my experiences with my 02 SC with 29k miles on it and how dirty the tranny, coolant and rear diff fluids were on the flush I did. Goes to show you that it truly is not mileage, it's date or miles that you need to go by.

kennylexsc

can you use this Mobil 1 Synthetic 75W-90 Gear Oil on our sc 430 for rear differential fluid ?

please advise,

thanks

BNR34

iTrader: (1)

Personally as long as the weight is correct, all oil are the same. Synthetic just last longer, which is nice on a differential since you don't change it often.

So for your question, yes Mobil 1 Synthetic 75W-90 Gear Oil would work.

TriniLex

How often is the diff oil suppose to be changed?

rustfarmer

IMHO the change interval on diff fluid depends on many things. I have seen many things. I have seen many hi-po cars with limited slip diffs run 100K between changes with no apparent harm, however I do not recommend this. Using top of the line fluids is wise and should allow longer change intervals. Changing at 35K seems overkill to me, however the more often you change it the better is certainly true. The most important change is the first one, as new parts always wear the small imperfections off as they break in and thus those tiny metal shavings in the fluid should be flushed out. After the first change of the "break-in" fluid I believe 50K is about the right mix of not wasting your time and $, but how hard you drive should be a factor.

JLeroy

I just changed rear differential fluid in my 2002 Sc430 today. I have no synthetic label on the back of my diff. so I used 80W-90 API GL-5. I have all maintenance records from previous owner and I am pretty sure that this is the first time rear diff fluid has ever been changed, that's 12 years and 105K miles later. Fluid looked fine, somewhat milky greenish-yellow with some black crud on inside of the drain plug. It took about an hour of light work, I used method and instructions posted online, http://www.lextreme.com/differential.html it was a piece of cake. I second the DIY approach on this, my cost was <$20, skill level = easy.