VLSD swap/stub shaft issue

[jacksoni]

I know this swap has been done a lot and posted here. I have looked at hundreds of posts, some of which identify the same issue but not totally addressed my question. I just swapped a VLSD from a J30 with 3.92 gear into an open diff with 4.08. With the slightly smaller pinion, for fit to be correct, shims move the differential carrier to the right (passenger side) about 5-6mm. Backlash is correct. The stub shafts from the VLSD were swapped as well and when installed, the right shaft is moved out that same 5-6mm. I see that some aftermarket LSD's have different parts if going into an open or VLSD diff, presumably for this reason.

I am concerned about the axle shafts bolting up correctly (compressing/relaxing the CV joints) and if running the rear this way with the axle shaft out on the right (dirt etc with access to the shaft/seal) is a problem.

Thanks for any thoughts/experience.

[PapaSmurf2k3]

Couldn't you just bolt the whole pumpkin up in instead of swapping the guts? I would think at worst, you'd have to change the half shafts.

[jacksoni]

Point was I wanted a LSD in the 4.08 gears.

[Hijacker]

I'm a bit confused on how much work you've done with regards to this swap. So the J30 guts went into a 240 carrier. You swapped the 4.08 ring gear to the J30 diff unit. You did not swap pinions. Somehow, the diff ends up shimmed too far in one direction. Am I about correct?

http://importnut.net/240sx-lsd-swap/

from the looks of it, you'll need the proper output shafts. J30, NA Z32s, and 240s all use different length outputs.

Double check the ring gear from the J30 has a stamp on the side that reads "47:12". You mentioned a smaller pinion, but a J30 R200 and a 240 R200 both have 12 tooth pinion gears.

The ring gear from the J30 is indeed thicker than the 240, so that would account for the shift to the right. 5-6mm is quite a bit of shimming shift though, since the shims only go up to 2.65mm.

When I did my R200V upgrade years and years ago, I landed a differential from a JDM S13 with output shafts. It was literally a direct swap. While I'm fairly certain that you only need to swap the output shafts and just ensure backlash, teeth mesh, and preload are set right in the open diff carrier, there shouldn't be too many differences between R200s to qualify such radical differences between the two.

If you can do me a favor, I'd like to know the flange thickness for where the ring gear bolts to. I'd like to compare the dimensions of the J30 diff to the S13 diff.

[jacksoni]

OK, is possible I have miss spoken about some of this. I have two carriers, both ABS with the longer pinion with pickup. One (the 4.08) has the small bolt mounts at the front (S13 style as I understand) and the other has the large rubber mount type as on S14. At this point, being several years past and some came from the guy from whom I bought the car, I do not know the exact source of these parts. You are correct, both pinions are 12 teeth. The ring gear for the 3.92 is considerably thicker (and 47 teeth) than the 4.08 (49 teeth) however. I swapped the ring gear from the 4.08 onto the VLSD differential, rearranged the shims that had been on the open 4.08 so the backlash was correct, which worked well, and used the output axle stubs from the VLSD. In this configuration, the axles shift to the right as I said in my original post. I have seen this issue in other posts about this sort of swap. I am sorry, I have swapped the parts back to their original positions so I can't measure the thickness of the VLSD flange. The open flange is .433"/11.0mm measured at the bolt hole. As the VLSd carrier is two part to allow access to the silicone containing canister, it may well be thicker and from memory looking at it, I think it is but as I have the rear now sealed with lube, I'm not going to take it apart again. This thread, though different parts source, is dealing with the same question I had originally: post6285865.html?hilit=vlsd swap#p6285865 If indeed the J30 and 240 have different length (not the right/left difference) stub axles this would explain the discrepancy. I have also seen that the ring and pinion have different part numbers for open and LSD diff carriers which also could be a factor. Anyway, thanks for your suggestions. I have fixed my problem (recalculated the gears I want/need and decided to go with the 3.92 because of likely slippage at speed/high rpms.)

[Hijacker]

It should be thicker. I was really curious to compare the J30 VLSD flange to the S13 VLSD flange to see if there really is a major difference in the internals. I can tell you for certainty I swapped a standard S13 open diff 4.08 ring gear onto my VLSD and had no hassle setting the preload. Also, if you ever feel like it, measure the length of the output shafts, specifically just the length of the shaft. I'd like to compile all these differences into a helpful guide for people who want to do LSD upgrades.

The non-ABS carrier (pumpkin) is indeed shorter. It was a nomenclature issue.