Our 2IS has and an open diff and I'd like to get some power to the ground without the microprosser braking a wheel or chopping power. As of this writing, here is what I know.

Bottom line is we want this:
41301-53051, CASE SUB-ASSY, REAR DIFFERENTIAL
** OEM LSD Torsen RING CARRIER ASM ** If you want the OEM Torsen for ease of maintenance that is.

************
IS250 AWD = A760H trans w/4.100 gearing
IS250 RWD = A960E trans w/3.909 gearing

IS350 AWD = A760H trans w/4.100 gearing

IS350 RWD = A760E trans w/4.083 gearing <<** My Target, yours may be different.
** 2013 LEXUS; IS250/350 (GSE21L-AETLHA), USA SED 2GRFSE ATM
************

A "Where Used" shows PN: 41301-50031 is used here:
41301-50031 CASE SUB-ASSY, DIFFE (OEM 2 pinion, ring gear carrier assembly)

Date range, Model, Frames/Options for that open diff...
08/2005-03/2013 LEXUS; IS250/350 GSE2*
04/2013- LEXUS; IS2xxx/3xxx ASE30,GSE3*
09/2014- LEXUS; RC350/300/200T ASC10,GSC1*
04/2009- LEXUS; IS250C GSE2*
01/2001-06/2010 LEXUS; SC430 UZZ40
01/2005-11/2011 LEXUS; GS30/35/43/460 GRS19*,URS190,UZS190
12/2011- LEXUS; GS2xx/350/450H ARL10,GRL1*,GWL10
02/2006-11/2011 LEXUS; GS450H GWS191
04/2007-08/2012 LEXUS; LS600HL UVF46
09/2012- LEXUS; LS600HL UVF46
**********

We need to keep our Ring and Pinion:
41201-59176, FINAL GEAR KIT, DIFF (RATIO:49/12=4.083:1)
08/2005-03/2013 LEXUS; IS250/350 GSE2*
04/2009- LEXUS; IS250C GSE2*
**********

It needs to fit this housing: Keep in mind the ISF/RCF get the finned housing. A different PN.
41111-30120, CARRIER, REAR DIFFERENTIAL (Housing, everything goes in here)
08/2005-03/2013 LEXUS; IS250/350 GSE2*
08/2006-08/2012 LEXUS; LS460/460L USF4*
04/2007-08/2012 LEXUS; LS600HL UVF46
09/2012- LEXUS; LS600HL UVF46\
**********

All four Bearings:
90366-45056 (BEARING, TAPERED ROLLER (FOR REAR DRIVE PINION REAR)) Fits Everything
90366-34024 (BEARING, TAPERED ROLLER (FOR REAR DRIVE PINION FRONT)) Fits Everything
90366-50087 (BEARING, (FOR REAR DIFFERENTIAL CASE)) Fits Everything (X2 ea)
**********

Rear Cover Assembly:
41108-50050, COVER, REAR DIFFERENTIAL CARRIER
08/2005-03/2013 LEXUS; IS250/350 GSE2*
12/2007-07/2014 LEXUS; IS F USE20
04/2009- LEXUS; IS250C GSE2*
01/2005-11/2011 LEXUS; GS30/35/43/460 GRS19*,URS190,UZS190
02/2006-11/2011 LEXUS; GS450H GWS191
08/2006-08/2012 LEXUS; LS460/460L USF4*
09/2012- LEXUS; LS460/460L USF4*
04/2007-08/2012 LEXUS; LS600HL UVF46
09/2012- LEXUS; LS600HL UVF46
**********

Drive Flange front of Pinion Gear: indicates input splines are the same for LSD equiped cars... =)
41204-30040, FLANGE SUB-ASSY, REAR DRIVE PINION COMPANION, REAR
08/2005-03/2013 LEXUS; IS250/350 GSE2*
04/2013- LEXUS; IS2xxx/3xxx ASE30,GSE3*
12/2007-07/2014 LEXUS; IS F USE20
09/2014- LEXUS; RC350/300/200T ASC10,GSC1*
04/2009- LEXUS; IS250C GSE2*
09/2014- LEXUS; RC F USC10
05/1993-07/1998 TOYOTA SUPRA JZA80
04/1991-06/2000 LEXUS; SC300/400 UZZ30,JZZ31
01/2001-06/2010 LEXUS; SC430 UZZ40
08/1997-12/2004 LEXUS; GS300/400/430 JZS160,UZS16*
01/2005-11/2011 LEXUS; GS30/35/43/460 GRS19*,URS190,UZS190
12/2011- LEXUS; GS2xx/350/450H ARL10,GRL1*,GWL10
02/2006-11/2011 LEXUS; GS450H GWS191
10/2015- LEXUS; GS F URL10
10/1994-07/2000 LEXUS; LS400 UCF20
08/2000-07/2006 LEXUS; LS430 UCF30
08/2006-08/2012 LEXUS; LS460/460L USF4*
09/2012- LEXUS; LS460/460L USF4*
04/2007-08/2012 LEXUS; LS600HL UVF46
09/2012- LEXUS; LS600HL UVF46
**********

The Axles used indicate the Carrier Side Gears are the same throughout. =)
42330-30160 (SHAFT ASSY, REAR DRIVE, RH)
08/2005-03/2013 LEXUS; IS250/350 GSE2*
12/2007-07/2014 LEXUS; IS F USE20
04/2009- LEXUS; IS250C GSE2*
01/2005-11/2011 LEXUS; GS30/35/43/460 GRS19*,URS190,UZS190
02/2006-11/2011 LEXUS; GS450H GWS191

42340-30160 (SHAFT ASSY, REAR DRIVE, LH)
08/2005-03/2013 LEXUS; IS250/350 GSE2*
12/2007-07/2014 LEXUS; IS F USE20
04/2009- LEXUS; IS250C GSE2*
01/2005-11/2011 LEXUS; GS30/35/43/460 GRS19*,URS190,UZS190
02/2006-11/2011 LEXUS; GS450H GWS191
**********

Now, the SWAP:
41301 CASE SUB-ASSY, REAR DIFFERENTIAL **WANTED THIS RING CARRIER ASM**
41301-53040 12/2007-07/2014 // IS-F, GS30/35/43/460, LS460/460L (OPEN), $1,005 <<NO GOOD
41301-53050 (08/2009 - 04/2012) // 12/2007-07/2014 USE20 ((USE20 ONLY), $3,400 <<GOOD
41301-53051 (05/2012 - ) 1 $3,800 <<BETTER
41301-53051 12/2007-07/2014 LEXUS; IS F USE20
41301-53051 09/2014- LEXUS; RC350/300/200T ASC10,GSC1*
41301-53051 09/2014- LEXUS; RC F USC10
41301-53051 09/2012- LEXUS; LS460/460L USF4*
/////
41110 CARRIER ASSY, DIFFERENTIAL, REAR // Uses this Gear Set
41110-53290 FINAL GEAR RATIO=47:16=2.937 (08/2009 - 09/2011)
41110-53291 FINAL GEAR RATIO=47:16=2.937 (10/2011 - 04/2012)
41110-53292 FINAL GEAR RATIO=47:16=2.937 (05/2012 - 07/2014)

Part 41110-53292 (CARRIER ASSY, DIFFERENTIAL, REAR) was found on the following models:
12/2007-07/2014 LEXUS IS F USE20 41-01: REAR AXLE HOUSING & DIFFERENTIAL
09/2012- LEXUS LS460/460L USF4* 41-01: REAR AXLE HOUSING & DIFFERENTIAL
**********

OR This for $1,850
http://osgiken.net/c-1280302-limited...ntial-tcd.html
[LSD] - LEXUS; IS-F (USE20) SKU: TY401-HC
[LSD] - LEXUS; IS350 (GSE21) SKU: TY391-HC

^^ but why the Different PN for 350 vs F?? Clutch Pack Setup or ? A phone call is needed.

https://frsport.com/OS-Giken-TY391-H..._p_231987.html
http://osgiken.net/ag-1340382.134061...1-2gr-fse.html

http://www.differentials.com/eaton-d...truetrac-faqs/ << Called them. The have nothing to offer. Mostly Domestic and Yoda Trucks.

That is All for now. I haven't fully explored the GS line but you all know the FRS LSD drops in IS250. the C model gets the larger housing like the 350 and the ISF/RCF.

 

Don't forget you can swap in a 2010+ IS-F Torsen LSD into the IS350 carrier OR another not mentioned aftermarket opinion is a ATS Carbon LSD (down under $1300 now!) : https://www.nengun.com/ats/lsd-carbon

The updated pricing on the ATS unit has me considering an upgrade on my 350 now. Hmmmmm.

 

Thanks. Thats what all the leg work up there is all about, getting that warm fuzzy that if I snag a used LSD carrier from a previously equipped F, RC, LS460 that we are good to go. I've set up roughly 40+ diff's so I'll do my own.

So, the linked content mentioned everything but DD. But I've never heard of them. It's to bad the Eaton Trutrac doesn't have a diff for us. Simply and effective worm drive like the OEM Torsen unit. From having other cars w LSD, i think it would make this much more predictable which is what I want.

 

Both the IS-F and IS350 OS Giken TCD units share the same number the clutch packs (28). Perhaps the slight design or part number difference has to do with the different final drive ratios (2.94 for the IS-F vs 4.08 for the IS350)?

 

^^ I don't see that as a factor if the bearings, housing, axles, and ring gear offset are the same which they must be for the OEM open diff to interchange. The problem for us is finding the needle in the haystack on fleabay if that is our path.

It could be the type of LSD. Where:
1-way locks under acceleration only.
2-way locks under both acceleration and deceleration.
1.5-way locks under acceleration and incrementally under deceleration as the load increases but never as much as 2-way does during hard engine decel.
Notice the link from Gville (carbon diff) has both 1 and 1.5-way. A 2-way **may** make the ABS unhappy during a corner deceleration and/or make the back end lose traction easier if you overdrive a corner. Be careful on wet corners with this one.

 

Another option... Cusco LSD and buy the setup you want regarding post above.
http://www.cusco.co.jp/search/en/ind...=&category=lsd

 

Any interest in a group buy if we can all pick a product/manufacturer??

Mind you I only want the LSD unit. I'll install myself.

 

If you can build your own FD21A, I would suggest the following:

1) diff carrier = 41111-30130 (this rear diff carrier has the fins in the cast iron)
2) diff breather = 90930-03077
3) Final gear kit (ring and pinion): 47/11 = 4.273 = 41201-29118 (ole SC400 FD) or what you have 49/12 = 4.083 = 41201-59176
4) IS F rear diff Al multi-finned rear cover = 41108-53040
5) OS GIKEN Traction Control LSD = TY391-HC
6) Polyurethane or Al rear differential mount bushings.

Of course new bearings and seals, like you have listed. I wouldn't worry about the OEM torsen case. The GIKEN is far better. I already bought a GIKEN LSD earlier this year.

 

Thanks for the numbers. Looking to run stock gearing and likely just an OEM case. Perhaps in the canyons it may need the cooling but it should be fine doing DD....

So you have the OS Giken listed above in a IS-350?

 

15% off the OS Giken LSD this weekend (regularly $1850) with promo code BLACK...I am fighting the urge to buy it: https://frsport.com/OS-Giken-TY391-H..._p_231987.html

 

carbon unit direct fit?

 

Yes, it replaces the factory open diff like all other aftermarket and OEM LSDs.

 

Apparently I didnt subscribe to my own thread...

It should be noted that all but the finned ISF housing/case from 2010 will require grinding/relief to install any of the LSD units....

Look here... http://figsengineering.blogspot.com/...ation.html?m=1

 

^Correct, but if you have the ability/skills to install an LSD, you'll be able to easily clearance the housing.

 

Here's a screamingly painful deal - 2015, RC-F, 2.937:1, OEM LSD, Finned case and all that jazz for $1,500 on fleabay...
Adding to the list of cases and three letter codes for donors gives us this "2GJ"