PlotPoint

The Lexus dealership said I needed to get 90w gear oil for my first gen LS400, but that they only carry it in bulk (in tanks). Called a Toyota dealership and they gave me the same answer (first said he thought he would have it in small containers but that it was probably synthetic and would be very expensive). He then came back on the line a few seconds later and said that he did not have it (I seriously question whether he actually checked). Any ideas where to buy this? Need it today.

Also, a search in these forums say that I should get "SAE 75w90" but the last time this work was done my records show the mechanic (Lexus trained) used "GL5-80w90N". What is the difference (and does it matter?).

There's an AutoZone near me if that would work. Can't believe I can't find this. I will try a few more Lexus dealerships. Tx for any info!

PlotPoint

Ok, please disregard as I think I found out what I need. I called yet another Lexus dealership and got a better answer. They use MOBIL in their bulk tanks, so that is what I am going to buy at an auto parts store. He said there is a significant difference between 75w90 and 80w90 and that the owner's manual will answer my question. Said to make sure the API# listed in the owner's manual is on the bottle of what I buy (API=American Petroleum Institute). Problem solved!

SpencerT

Autozon will work
I assume this is for your differential?

75w90 is a mix of 75 and 90 weight.
80w90 is a mix of 80 and 90 weight.

75w90 is what the forums recomend and what I used.
will the other work? Probably.
I would go 75w90 though.

timmy0tool

iTrader: (7)

i'm using royal purple 75w90 here bought from autozone, but i'm sure it's overkill since we don't have limited slip differentials. mobil 1 gear oil will suffice.

PlotPoint

Thanks. I saw the forum recommendation and am going with that (75w90). Wonder why the last mechanic did the 80w90.

My owner's manual does not specify the weight for the rear differential fluid (at least the manual I have). Just says to replace it every two years.

Just got off the phone with AutoZone and they are holding the last two Mobil SAE 75w90, which is synthetic. He also has Valvoline, 75w90, which is NOT synthetic. Do you know which one I should buy? Thanks very much. I'll google this too to see what I can find out.

timmy0tool

iTrader: (7)

synthetic of course. the regular stuff would be just fine since this is just gear oil, but why not spend the extra $ for more protection in the long run?

PlotPoint

That's what i got. But is it supposed to have an "LS" in the title? Mobile 1 LS 75w90 is what I got. When I read up on Mobile 1 gear oil on their website, looks like the LS stands for limited slip differential, which my car doesn't have, if I am not mistaken. I read that it has an open differential. Guy said the stuff would work with conventional and limited slip differential.

If anyone knows any differently, let me know, otherwise I will keep this.

SpencerT

Yes the "LS" is the right stuff. That what I used and all is well.

LScowboyLS

according to the Toyota engineers who designed your rear end, unless you drive in weather that gets below 0° F, then straight 90W that meets API spec GL-5 is what is recommended.

and for folks who drive in weather that goes below 0° F, then they recommend 80W-90 or straight 80W

source: Lexus factory service manual - page SA-45

because it's correct


not saying that there is anything wrong with 75W-90, it is just suitable for a wider range, but the previous tech was just going by the Lexus factory specs, can't get much better than that! - I guess a lot depends if you ever plan on driving up to any of the cold states during winter! - at least with the Mobil 1 - you are good to go, even at -38° F

but like in my case, I live in Alabama, it never gets below 10° F here, and even that temp is about once every 10 years, so straight 90W is fabulous if you avoid cold weather like me!

PS - I don't trust anything out of a bulk drum, too easy for greedy dealerships and quicky-lube chains to cheat!

PlotPoint

Toyota engineers designed my rear end? News to me! And that explains a LOT. ROTFL.

I live in Southern California and it hasn't been below 47 degrees in something like a Century (don't quote me on that). So why would he put in GL-5 80w90? You said that's for people who drive in weather below zero degrees. I didn't see anything that said just straight 90w, so that wasn't even an option.

I got what was available...the 75w90 then called around to try to figure out if it would work (all backwards, I realize, but was out of time). I talked to mobile one and they said as long as the car was GlL-5 rated it will be fine. And you just answered that question (GL-5 it is), so yay!! All good. Car shifts like butter now. WOW. What a difference a llittle maintenance makes..

PlotPoint

Cool! My car is loving this stuff -- just got back from a test drive.

PlotPoint

Not sure I should be getting my car info from ehow, but see below for what that site says about the difference between the 75w90 and the 80w90 gear oils:

For what it's worth, a mobile one customer service rep yesterday told me I could use what I bought, which was 75w90, even though my car has an open differential. I called to specifically ask that questioin. The info below seems to contradict that: It says it's 80w90 that can be used in both conventional and limited slip differentials. Wouldn't 80w90 have been a better choice? Does 'conventional' mean the same as 'open differential?" And why is this forum recommending 75w90 (it's in a sticky somewhere) if the service manual is saying "straight 90w"? Btw, I don't know what straight 90w means, i.e., what a Mobile 1 label on a bottle of gear oil would look like for straight 90w. I believe you said that i what was recommended by the service manual, GL-5 rated and straight 90W.

I got the 75w90 because that is all they had and also because that is what it says in one of the forums' mother threads. I think that info is in one of the stickies but can't say for sure. I just recall writing it down as 'the' gear oil to use for this first gen LS400.

Btw, the feel of the car shifting is vastly improved.

Anyway, here's the ehow quote:

75W-90
The 75W-90 gear oil is used under extreme pressure conditions and is recommended for limited-slip differentials and for use in colder climates. Used in heavy duty manual transmissions, final drives and axles, high temperatures will not effect the heavy film left by this oil.

80W-90
The 80W-90 gear oil can be used in extreme pressure conditions and as a lubricant for non-synchronized manual transmissions in heavy duty trucks or buses. This gear oil is recommended for conventional and limited slip differentials.