Ghump

Last month I got involved in a discussion about installing a 3.769 Diff. in my 2002 SC430. It turns out there are some difficulties in swapping diffs. Since then I have successfully installed one in my SC. It took me some time and research to figure out what was needed and how to do it, so I thought I would post my findings for anyone interested in doing the swap. BTW, I didn't want to spend the $$ for the Supra LSD ($1500 to $1800) , which would have been a direct swap. I was looking for a way to used a newer 3.769 diff. from an SC, GS or LS. There are many 3.769 diffs that will work, but the problem is that the newer diffs have a different style of axle. The 2002 thru 2005 have what is called an axle sub-assembly, while the 2006+ the axle goes directly into the carrier. This is not a how to, but rather what is needed:

1. If you have a 2003 thru 2005 SC430 your axle sub-assemblies can be removed for your existing diff and used directly in a compatible 3.769 diff. The sub assembly is knocked out with a drift (rod) and hammer. They are splined and have a compressible c-clip that holds them in place. You are the lucky ones. For reference that sub-assembly part # is 4130930060.


2. 2002 SC's have a different carrier style and different sub-assembly(4130924020) that will not fit into the newer 3.769 diffs....bummer...but it is still doable. You would have to acquire a set of the 4130930060 sub-assmeblies. I wound up buying a 3.769 diff from a 2004 LS430 for $250. I then bought a diff with those needed subassemblies for $247 and and installed them in the replacement 3.769 diff. It is now directly swappable in that 2002 SC.


3. Attached are two photos. The first is my original diff. Notice the 6 bolt sub-assembly and behind it the 8 bolt attachment on the carrier. The second is a diff from a 2004 SC430. Notice that it has the sub-assembly, but no 8 bolt attachment on the carrier. That 2004 carrier is the same style as most of the newer 3.769 diffs in 2006-10 SC's. In a 2002 SC it is also possible to swap out the axles to the newer style axles, but they are very hard to come buy and a lot more installation to do with swapping axles. P.S. the newer 2006+ axles are not easy to get because they are basically not rebuildable. You can't even get boot kits for them and there are no remanufactured ones that I have ever seen. 2002 thru 2005 axles have boot kits available and are easily available remanufactured.


3. Most of the Lexus diffs have two different bolts listed for the vertical stopper bolts that attach the diff arms to the body of the car. In photo #1 is the stopper bolt from my 2002. The 3.769 diff that I bought has a narrower bushing sleeve and my bolt from my 2002 would not fit through the sleeve. I had to buy the other bolt listed, part #9010912081 (also Toyota part number 90109A0054). The thread size of both bolts is the same, it is only that the shank in my bolt widened (see photo #1). The bolts are not very expensive.


I know this is kind of complicated and a little goofy, but the point is that it is doable for any 2002 thru 2005 SC430 and BTW worthwhile, the gearing change is very noticeable and spunky!! I got interested in doing this swap because I was going to install a Magnaflow catback exhaust and I figure if I was going to remove the factory exhaust, this would be a perfect time to do the diff...together they are great!!


Any questions...just ask!!

bacardi11

iTrader: (1)

very very nice

LexBrett

Can you pleas elaborate on the statement "would have to acquire a set of the 4130930060 sub-assmeblies. I wound up buying a 3.769 diff from a 2004 LS430 for $250. I then bought a diff with those needed subassemblies for $247 and and installed them in the replacement 3.769 diff. It is now directly swappable in that 2002 SC"

Are you saying that you purchased TWO differential carriers and interchanged some parts? I'm not sure if I follow. I understand you bought the ls430 differential, but what else? I see you out a lot of work into this..

Ghump

Yes, I did have to buy two differentials. The sub-assembly from my 2002 SC
is different than the ones on 2003 to 2005 SC's. As I pointed out if you have an 03 to 05 SC the sub-assemblies will fit directly into the 3.769 differential. It only us with the 2002 that have to find the later sub-assemblies. I learned the hard way. I bought the new differential and my sub-assemblies wouldn't fit. I then checked part numbers to find out what I needed. I think buying those sub-assemblies new is very expensive so I searched for a differential with the ones I needed. Confusing, I know, but its the only way to modify a 2002 SC. So, I paid $250 + $247 = $497 for everything I needed. Also about $10 bucks for the new stopper bolts. It's worth it!! The learning curve was a bummer, though!!

bacardi11

iTrader: (1)

Ghump
if you want a cheap way out Ghump is on the money open rear.
the 93-98 Supra is the best Posi

LexBrett

Since my car is a 2002, are you saying all I need to buy is the diff from a 2004 ls430 and some stopper bolts!?!

LexBrett

Oh so you bought the diff for a 2003-2005 sc430 and a 2004 ls430 for your 2002??

Ghump

You need a 3.769 diff and you need to acquire a diff that has the correct sub-assemblies that will fit the 3.769 diff. You could probably order the sub-assemblies from Lexus parts, but I think they would be $500 + dollars. That's why I bought a used diff with those sub-assemblies, removed them and put them in the 3.769 diff.

Bgw70

I am trying to follow this but I am having a difficult time understanding what is required. Try this,

1. If you have a 2002 SC430 purchase the following rear end parts.

2. Purchase a differential from 2003-2005 SC430.

3. Purchase axles or sub assemblies from 2003-2005 SC430

4. Bolt them on your 2002 SC430.

Is that correct?

LexBrett

Here is an MK4 differential for about $500 shipped. Looks beat up but the teeth look nice. I just don't know if I could handle the stress, time, and cost of the install (DIY most likely)..
http://www.ebay.com/itm/DIFFERENTIAL-JDM-2JZGTE-VVTi-TWIN-TURBO-AT-SUPRA-JZA80-ARISTO-JZS161-GS300-98-/271368117040?hash=item3f2eccdb30&vxp=mtr

Ghump

Bgw70,


Correct for the most part. You can purchase a 3.769 differential from several different vehicles. Mine came from a LS430. But some models of GS also have that diff. Of course the 2006 thru 2010 SC's definitely have the 3.769 diff.


The second diff I bought was simply to get my hands on those 4130930060 sub-assemblies. I found the diff on eBay from a 2004 SC that had those sub-assemblies. All this time I was checking parts diagrams online to confirm the part numbers. I didn't know for sure those sub-assemblies would fit until I bought that second diff, knocked out the sub-assemblies and put them in the 3.769 diff. They fit and I was happy for $547!!


BTW, I agree with Bicardi11...that Supra LSD is the best solution if $ is no object, I'm just not racing around much, wanted the pep and not the expense.

LexBrett

Did you install it yourself?

LexBrett

How about a 4.08 differential :-)

http://www.ebay.com/itm/JDM-TOYOTA-ARISTO-2-WAY-ATS-DIFFERENTIAL-4-08-GEARING-SUPRA-SC300-2JZGTE-MK4-/321641554541?hash=item4ae354a26d&vxp=mtr

Ghump

I did install it myself. I followed the instructions from one of the members who did the LSD and it was right on!! That's why I didn't post any instructions. None of it is very hard, more a lot to remove to get the diff out and getting the diff balanced on the jack correctly is a little tricky.


A 4.08 is quite an aggressive ratio. I know nothing about fitment on those, but I bet someone knows on this forum!! I think the 3.769 is a good compromise ratio for street and a little added pep.

bacardi11

iTrader: (1)

lex
in my Vett. I ran 4.88
with a 4.08 at 60 your RPM would be about 3000 great take off lose top end speed this is at 1 to 1 5th is over drive
that torque convertor you have what RPM?
just check my RPM gauge just over 6000 red line