I just finished swapping a 1995 J30 VLSD w/ ABS into my 89 240sx w/o ABS. I ran into some snags but in the end it worked out perfectly. Since ther are always questions about these swaps, I thought I would post a quick note on things to keep in mind if you are doing this particular one.

The great thing about using the J30 diff is that it is cheap. All you need is the J30 diff with output shafts, some JB weld, and a few washers. The bad thing is, the final drive ratio of the J30 is about 4% taller than the 240's (3.9 vs 4.08 respectively). Although this may theoretically make you somewhat slower off the line, the VLSD will WAY MORE than make up for it. I have heard of a guy with the SR dropping almost a second off his Qmile time after this swap. That sounds like a lot to me but the take home message is the VLSD will way more than make up for the longer gear.

1. When shopping at your local junkyard, make sure you get the J30 pumpkin and output shafts. The 95-97 output shafts will bolt right up to the 240. Also, try to get them to throw in the carrier bolts. The ones from the s13 are too short. If you don't have the J30 carrier bolts you can always get some from your local hardware store.

2. You will need to swap the diff cover from the s13 onto the J30 pumpkin. The J30 uses 2 rear mounting bolts while the s13 uses 4.

3. There will be an ABS sensor hole near the input shaft on the J30 diff. Close this up with some JB Weld.

4. The J30 pumpkin is about 1/2 inch longer than the 240's. Don't worry about it. It will fit just fine in both SR and KA applications.

5. The carrier bolt mounts are different. The s13 uses solid mounts with no bushings. The J30 uses rubber bushings. To make the J30 diff bolt up, you will need to buy some washers to take up the space where the rubber bushings would go. I used 7/8" ID and 2.5" OD. (I think maybe 3/4" ID would actually work better). If your J30 diff came with rubber bushing try to include these in your install as they will make everything fit more snug since they are somewhat compressable and will act like lock washers. Just play with the wahers and bushing until you find what combination fits best.

Now you can bolt that bad boy up and you are ready to go. I hope most of this made sense. It is not intended as a how-to but rather a supplemental guide for this exact application.

Good luck,

dave

Quote »the final drive ratio of the J30 is about 4% taller[/quote]Taller and longer, mean 2 different things...a taller gear would go up in numerical value, a longer gear goes down in numerical value...The j30 is 4.06% longer, not taller....just thought I'd help lessen any confusion here...

Is step #3 really necessary? I just left it open when I did my swap into my 95 non-abs s14.

One more thing that you could add, is that you will also need to replace the speedometer pinion in your transmission to correct the 4.06% loss in speed. When you're your speedo says 100mph, you are actually traveling 104mph....it could get you into trouble down the line...

Only problem is, nobody seems to have the proper speedometer pinion, (19 tooth, assuming the s13 and s14 trannies are the same), to correct it...courtesy nissan says they're sold out, and parts.com doesn't know that they exist...

I'm currently experimenting by purchasing some from a 300zx and pathfinder to see if I can find one that will mate up....

Thanks for the input and clarification. I actually went back and forth as to whether "longer" or "taller" was the correct term.

As far as step 3, I didn't know if it was necessary or not so I filled the hole just in case.

Keep me posted on the speedometer pinion. I'm not too worried, for now, I just keep in mind that I am going faster than my speedo says.

Nice writeup, very good info. Way to go dave!!

Hey Dave, how long are the "carrier" bolts for the 95 j30???I just bought mine off e-bay and I need to know cause I'll have the exact same setup as you (s13 w/ j30 LSD). Also, are the 3/4 ID washers really neccessary????

just one question? what driveshaft do youneed to use, i got a 91 coupe with non abs

SRdave240 wrote:4. The J30 pumpkin is about 1/2 inch longer than the 240's. Don't worry about it. It will fit just fine in both SR and KA applications.

Mine ran fine for a long while and then the extra stress due to the longer shaft caused the pinion gear to shear down to razor edges. But it seems like different people get different results, you either get lucky or you dont. I got another diff and a custom one piece driveshaft.

RatedR wrote: Also, are the 3/4 ID washers really neccessary????

Yes, they actually are. A buddy of mine installed it on his 240 w/o the washer. The stress caused the subframe to crack after 6 months. Some ppl don't have this problem (lucky?) some ppl do, I'd rather not chance it.

I got the bushings/washers etc from the guys in my sig (frsport) - you have to aim them tho as they don't carry it on the site I think.