Lexus IS Forum banner

Official OEM LSD thread: Case closed, important info inside

153K views 260 replies 53 participants last post by  Steve Theodore 
#1 · (Edited)
I think I found there may be a way to tell the difference between an open diff and an LSD diff without taking the rear cover off. Underneath the diff, when you jack up the car, there will be a sticker that says M96 or M85. So far only one other guy and myself have confirmed that our open diffs have M96 on them but we'll need some more people to inspect their cars to confirm the assumption. Where you are looking is right under the nose of the diff where the pinion goes in. Please post what your door number says (BO2A=Open, BO2B=LSD, BO2C=LSD) and what your diff says (M85 or M96), thanks!





Here is the information we gathered. Now if you have an open diff in your IS and want to install an OEM LSD differential, you know what to look for!

Gathered information. (Confirmed)

1. M96 sticker equals open Diff.
(auto or manual)

2. M98 sticker equals Locking diff. (LSD)
(auto 3.9)

3. M85 sticker equals Locking diff. (LSD)
(manual 3.7)
Thanks to 2JZ-adm for working with me on this and everyone who contributed!
 
See less See more
2
#3 ·
One thing it *could* be a distinction between is gear ratios though so we'll need to know if the cars we are gathering information from are auto or manual. I think what I read in your thread was auto's have 3.73 gear ratios and manuals have 3.91's? Here is my information to get this rolling...

2001 Auto, BO2A on the VIN sticker, M96 on the diff
 
#8 ·
FINALLY SOME PROGRESS! Went to the junk yard today
To take back the diff. I bought that was supposed
to be an lsd but ended up being an open.
Well after digging through six diffs. we found a diff
with a m85, low and behold a lsd. I will post pictures later
and count the teeth to see if its auto or manual.
Yaaaaay!
 
#12 ·
Okay, I know i said I would post pictures and
I will, tomorrow.
Atleast we know that the stickers have somthing to do
with open or locking at this point.
Another thing to look for that wasnt posting in this thread;

http://my.is/forums/f88/pictures-my-lsd-non-lsd-carriers-263213/

If you happen to go diff. hunting and your looking for that M85 sticker,
check any diffs. that may be missing a sticker
by looking through the output sides of the diff.
(if there isnt any output flange still connected to the diff.)
You can tell right away the difference between open and locking.
Will most definitely post a few pics tomorrow.
 
#13 ·
has anyone driven on an stock auto non-LSD diff (or LSD diff i guess) and compared it to a stock manual LSD diff??
after boosting last summer with my auto tranny, the shortness of each gear became extremely noticeable and highly unpleasant to drive.

i was hoping that i could hold gears longer once i did my r154 swap but i don't really notice a difference (i guess it's because i now have 5 true gears as opposed to the 4 gears in the auto tranny (not counting 1st gear, which isn't really a gear obviously)).
i can't hold 1st or 2nd NEARLY long enough before my RPMs rise too much (it's not bad when driving aggressively, but since its my daily driver, i would say 80% of the time i'm trying to drive it normally, without going into boost. and the only way to stay out of boost is to shift through my gears WAYY more quickly than is comfortable).
once i'm in 3rd it doesn't bother me so much, but HOW THE HELL CAN I MAKE MY GEARS SIGNIFICANTLY LONGER??

(not sure how you say it. lower my gear ratios? make my gears longer? however you say it, i want to be able to hold each gear longer before feeling like i have to shift)
 
#14 ·
HOW THE HELL CAN I MAKE MY GEARS SIGNIFICANTLY LONGER??

(not sure how you say it. lower my gear ratios? make my gears longer? however you say it, i want to be able to hold each gear longer before feeling like i have to shift)
I dont know too much about gear ratios. The more gears you have the shorter theyre gonna be. I dont know how much more of difference between
changing the oem diff. for another oem. Then again, I dont really know.
You may wanna ask someone in the "Go faster" section, they probly would have more skill with that field, especially with you, being boosted and all.
Sorry, I couldnt help you more.
GL
 
#16 ·
Well said, brian. I actually wondered the same.
When I get off work, ill take pics of the diff
so we can get back to LSD's. On my sidekick
Posting right now, so I need to get to real computer
first. Still trying to locate the M98 sticker, kinda wondering
If it even exists. That guy coulda seen a smudged M96.
 
#17 ·
Thanks! It would be sweet if more people would just put a jack under their car and check what sticker they have and report back so we can get some definitive information! :) It only takes about 2 minutes to check...
 
#20 ·
Alright here they are finally!
I also just noticed that my M85 carrier has a four instead of
a 3 next to it and a different japanese symbol.


Differential sticker (confirm LSD, unconfirmed ratio)
M85 with 4
Automotive wheel system Automotive tire Personal protective equipment Rim



Also supplied a picture of inside the
diff. through a ouput side.
Auto part Circle Wheel


If you were to look at an open diff.
you would pretty much see straight
through it. As you can tell, there is some
kind of locking gear or something in the
middle. Hopefully some other members will
contribute to our movement.;)
 
  • Like
Reactions: LO 21
#21 ·
^^^ that we will. THANK YOU!! +rep
 
#23 · (Edited)
Gathered information. (Confirmed)

1. M96 sticker equals open Diff.
(auto or manual)

2. M98 sticker equals locking diff.
(auto. 3.9)

3. M85 sticker equals Locking diff.
(manual 3.7)


I feel pretty good about this since Ive had conformation on these
and this seems to be the only logical explination for the numbers.
any of the other diff numbers other than the MXX stickers dont
appear to have any relation to gear ratio, or far as we can tell.
I hope this can help out alot of people searching for these things.
It was a long raod but thanks to Brian7, various members and myself
I feel its reached an end.
Thnaks to everybody who contributed!

CAM
 
#24 ·
my car will briefly be up on the lift tomorrow. is this something i will be able to see just from looking at the diff?

if so, i'll report back tomorrow (i'm expecting it to be M96, kanji symbol 1, #3 since i'm an '01 and 100% NOT LSD.)

for your three different diff codes on that last post, are those for auto or manual, or doesn't make a difference?
 
#25 ·
You should just be able to look under and see a sticker.
As far as the codes go, they're are mainly unconfirmed until
i pop open my carrier (M85/Kanjisymbol 2, #4) and count the ring
gear teeth. until then or when someone else can chime in, Im
not really sure how the diff codes corelate with auto and manual ratios.
dont worry, were almost there, i can feel it.:p
 
#26 ·
I will be opening my diff carrier tomorrow, to verify the ratio.
Even still, we will require some input from other members.
Come on, +REP will be given.
Just jack up the rear (properly),
take a look & post it up.
 
#27 ·
1. M96/Kanji symbol(1) & #3 sticker equals open Diff.
(unconfirmed ratio)

2.M85/Kanji symbol(2) & #4 equals locking Diff.
(unconfirmed ratio)

3.M85/Kanji symblol(1) & #3 assumed locking.
(unconfirmed ratio)


I have an 03" GGP automatic inside the driver side sticker is B03A=Open diff.

The sticker under the differential is M96 &#4, non'lsd.
 
  • Like
Reactions: 2JZ-adm
#28 ·
LeonHKS said:
I have an 03" GGP automatic inside the driver side sticker is B03A=Open diff. The sticker under the differential is M96 &#4, non'lsd.
Nice job contributing! +REPped. Wow, now we got another number combo.
to think about. I kind of have a feeling that gear ratios may not be represented in the numbers.
Cant say for sure unless we get someone else with an open diff. auto that has a m96/#3. So keep posting people.:)
 
#33 ·
I knew the mods would probly move it here anyway.
Well, here it is the moment ive been waiting for all week.
opened up my diff. and counted the teeth. theres only 41.
which im guessing means its a manual 3.7 since the auto
has 43. kinda was hoping for an auto lsd, but that would
just be too easy, because nuthin ever is. I really feeling
that differential numbers may not have anything to do with
ratios, at least what we can tell.
Come on peeps contribute a little more.
 
#34 ·
I guess it's OK, you might get slightly better gas mileage since the RPM's will be lower on the freeway. Downside is it might be slightly slower than before..

Edit: Check around the ring gear for any numbers, it might have the ratio stamped on there.
 
#36 ·
naaaw, just a part number 2000-2400588.
ill probly look it up tomorrow or sumthing.
still pretty psyked that I found an LSD,
and now Im a little more educated on finding one.
Good Job Brian!
 
#37 ·
not sure if it helps or not. i have an 02 auto nonlsd. today we threw the car on a lift and m98 was the number listed. thanks
 
#39 ·
The 3.91:1 LSD I have has M98 on it aswell. No idea what year it came from though.

I'll see what my non-lsd from my 01 has on it sometime soon.
 
#40 ·
You know what, I hate stickers. Everytime I think I get a little closer,
more info comes that just puts me further from a conclusion.
Wutever:rolleyes:

Oh, thanks for the contribution! If i wouldnt have taken your advice from
my original thread, i woulda never opened up the carrier and found out it
was actually an open diff.:approve:
 
#43 ·
okay, i found something today. kinda contradicts EVERYTHING about the M85s. found M85-3 off a MANUAL.

what the hell could that mean.
that means LSD manuals could have come with M85-3 AND M85-4??
which is which then? maybe the 3's and 4's after the japanese symbol dont represent gear ratio after all..
 
#44 ·
Yeah, I guessed that earlier on in one of my post in the LSD
thread. Still have no idea what the kanji/# corresponds with.
Only thing we figured out so far for sure is that M85 is an LSD
M96 open and still workin on the M98 since someone posted
They had an LSD with this sticker
 
#45 ·
well just called around to verify the part number on the ring gear in the
LSD diff I picked up. First I called South Bay Lexus and they said that it
was most likely a toyota part number. Then I caled my uncles dealership
and the guys I usually deal with in parts are off on monday, so all I got
was some guy brushing me off saying they dont pull up numbers. i told him
I do it all the time there, so he asked me the number and told me it wasnt valid
before I could even finish saying it. Im fu*in frustrated right now.
 
#46 ·
The M98 LSD I have sitting here on the bench has a "4" after the japanese symbol.
 
#47 ·
was it from a manual or auto IS, and what year?

any word on how the hell the M85-3 i found is also from a manual IS like your M85-4?
before i pay to get this thing shipped to me, is there any way i can dictate to the guy how to open it up and check what the gear ratio is. i need the 3.7 for sure (i dont wanna say i need the "manual" one cuz that could mean anything at this point)
 
#50 ·
sorry, i've never seen one of these off the car in person. how can i dictate to this guy how to open it up? just remove those bolts on that bottom piece that looks grayer than the rest of it in this picture?



when he opens it, i'm guessing this is what he should see?
and the teeth you guys mention that he needs to count for me are obviously these large ones i'm guessing?
can someone please confirm that 41 teeth is for 3.7 gear ratio and 43 for 3.9.
or how else have people in the past figured out if they have a 3.7 diff or 3.9?

 
#52 ·
sorry, i've never seen one of these off the car in person. how can i dictate to this guy how to open it up? just remove those bolts on that bottom piece that looks grayer than the rest of it in this picture?



when he opens it, i'm guessing this is what he should see?
and the teeth you guys mention that he needs to count for me are obviously these large ones i'm guessing?
can someone please confirm that 41 teeth is for 3.7 gear ratio and 43 for 3.9

Yes, you have it correct. The rear cover needs to come off(8 bolts).

I'm not sure how many teeth the 3.73 ring gear has, but the 3.91 definitely has 43. Considering there was no other ratio available for IS300's, if you find one that has something other than 43 teeth, it's most likely a 3.73. Unless you get the JDM 4.11 from the Altezza(I think that's what they came with).
 
Top