Ive located a 1994 J30 rear end for my neighbors car (1995 240sx) but I have some questions:

Did all J30's come with a VLSD?

What year J30 VLSD fits onto the 95+ 240sx?

What specific markings are on the housing to know if its a VLSD or not?

Is $350 a good price? (considering the J30 has larger gears then the stock 240 vlsd)

What other parts are we going to need to complete the swap?

I already did a search on freshalloy but couldnt find anything. So any help would be appreciated. Thanks in advance.

All RWD Infiniti US came with LSD that I'm aware off.

I will get you the LSD from a J30 for $325, if you still want one.

Andreas Miko

Andreas,
I sent you a pm. Just wondering if you received it? Otherwise I will resend. Let me know, please.
Thanks

Here's my diff swap writeup. The pics should tell you what to look for.

My Diff Swap (http://importnut.net/lsdswap.htm)

There is a note at the bottom regarding J30 diffs.

-Alex

You forgot to list that the J30 come with 3.90 gears which is better for any high HP 240sx. Droping the gears from the 240s 4.08 diff to the J30s 3.90 alls for more top end speed, higher speeds with every gear and will stop excesive wheel spin while driving the car on the street. If you have enough HP your car will not accelerate any slower. Droping one gear ratio is no big deal. I will give an example to this 300zx 4.08 rear end and 300zx TT has a 3.70 rear end.

Hmmmm...I didn't know that. My J30 info came form outside sources. I'll check into it.

-Alex

As far as the ratio is concerned, I've talked to a few people and the ratio is the same as the other R200V diff's. The only difference is that the diff uses an ABS sensor ring on the input of the diff. You can either replace the input with a non-abs 240's input or pick up a driveshaft for an ABS equipped 240.

-Alex

Stop asking other people and check a J30 service manual.

SR20DET & CA18DET 180sx S13 = 3.916, 4.363
180sx S13 95/9--- = 4.083

SR20DET S14 = 4.083

S13 - S14 KA24/DE US = 3.917, 4.083

Z32 NA =4.083

I will get the J30 Service manual figures, I will look at it one more time to be 100% sure, But J30 =3.917.

All figure above are from Nissan service manuals or Nismo Info book that I own. There are a lot more R200V diff combos but they are from 3.70--3.333 so they are way to low for use so I did not post them.

I found a 1995 J30 viscous VLSD with just over 100K miles. Supposedly it will install in my s13 without anything other than a cover gasket, or maybe shaving off that extra inch from the ABS sensor if it really won't fit. However, some sites i read said i needed to change to the appropriate axles? I'd like to be clarified if i should go ahead and buy this and it'd up without other modifications. Thanks.

First, most info you need is here: http://www.ka24development.com/index.html - big diff compatibility writeup.

Second, notice that this thread is over four years old.

Third, no offense but most of that info is wrong. Sigh.

The J30 diff will bolt to the S13, but you must use the S13 rear cover (not just the gasket, the gaskets are the same). The axles may or may not be different. Some J30s had five-bolt axles, some had six. ALL S13s in the US had six, so if your diff has five you need the J30 axles.

Next, the ABS issue. All diff casings with ABS are longer than those without. You can probably bolt it up and drive away but eventually (sooner rather than later) the carrier bearing on the driveshaft will fail. Easiest solution is to get a driveshaft from a car with ABS, which is correspondingly shorter. I have no idea what it would mean to "shave" the front of the casing, I can't see how that would work at all; you'd probably just end up with a worthless, wrecked diff.

Last idea - if the J30 diff has six bolt outputs, you can swap the guts and the outputs over to your S13 stock diff casing. You MUST swap the outputs over also, the output shafts for a VLSD are not the same as those for an open diff. You'd also have to swap the ring gears (but not the pinions) - the S13 and J30 don't have the same final drive ratio. In other words, stock S13 casing + stock S13 ring gear + J30 VLSD guts + J30 six-bolt outputs = not having to worry about the driveshaft. This will only work if you have six bolt outputs, or if you've got the five-bolt outputs AND the corresponding axles.

Go read the S15 diff install in the tech section, it talks more about the ring gear and such.

Thank you for the information. Although i will try to find an ABS driveshaft from a 240sx, i read this on 240sx.org.

"I have heard rumors that the J30 differential requires you to shorten the driveshaft by an inch due to the position of the ABS sensor but my buddy hasn't had any problems with his when he installed it in an S14. It's only been on for 2 weeks and the fit is tight but it works."

i see this guy is pushing his luck, but if worst comes to worst and i can't locate an ABS driveshaft, could i shorten mine like he said?

It's not something you can do yourself. Like shaving the diff casing (which no one can do). A driveshaft shop could do it - it has to be balanced so that when it spins at hundreds or thousands of RPMs it doesn't either fly apart or come loose and beat the hell out of the car and its occupants.

Putting the ABS diff in with a non-ABS driveshaft will work, but the bearing in the middle of the DS will not be aligned with the bracket. That's what causes the failure.

If you've got the right parts I'd honestly look into swapping the guts into your stock S13 casing.