J30 VLSD --> S13 housing and ring gear

[CaptainHenreh]

Evenin' folks.

The UPS man brought my 1995 J30 rear end today, complete with 6 bolt output shafts. I should also soon be in posession of a stock open differential. (i.e, not the one on my car, but a spare) So what I'd like to do is take the stock ring gear off the open diff, put it on the J30 internals, and put it all together inside the aformentioned stock non-abs housing.

So, I was wondering if anyone could scan some FSM pages for me, or if someone has downloaded the JDM S13 FSM from the internet, and could tell me if the information I require is in there. I feel pretty confident in my ability to do this, and it looks relatively simple, but I want to be sure. I also wanted to know what I should replace while I'm in there. The output seals for sure, and I'll use RTV for the 4 bolt cover. I'll also need torque specs for everything.

In fact, any information at all that anyone can think of, I'd appreciate. And yes, before you say anything, I have searched, many many times, and I have come up with a wealth of information. I just want to cover my bases.

[trpower7]

Why?? That sounds like one retarded idea. If it has 6-bolt output shafts those are the right ones. The gear difference is minimal: 4.08 vs. 3.96. All you have to do is swap rear covers; a five minute job. Be sure to get a cover gasket from Nissan, you'll need it. And why would you need ANOTHER open diff??? Just take your's off, swap the rear covers and bolt it on up. Sounds like you're making a really easy job a lot more difficult..........

[Dattebayo]

The tooth size on the open diff's ring gear is going to be an issue. Also, the FSM shows that the VLSD has 4 pinion male gears compared to 2 for the open, and there are differences in the 2 thrust washer sizes. I just dont think it can be done...

[CaptainHenreh]

The reason I want to swap housings is because I don't have ABS, so the housing is, what, .75 inches longer? And giving my driveshaft a shove doesn't really appeal. I'm going to try to fit it in there, but I wonder if it will fit.

To be honest, I'm mostly worried about my speedometer being off. And it was my understanding that it was as easy as "take parts out, put parts in, torque to specs, put cover on" to swap them out.

If I've been misinformed, I appreciate the correction. And the reason I was buying a second open diff was to be able to do the work on the housings without having the car be MIA during that period.

How many people with S13's have had fitment issues with the longer ABS housing and a non abs driveshaft?

[HashiriyaS14]

um i had ABSOLUTELY NONE. For s13's you just slip the drive shaft up over the top of the final drive end of the differential and down, it slides into place and then you bolt it. But thats with the J30 diff. And im not lying it took me 3 hours WITH beer breaks to do the whole thing. Just remember to get the 2 chassis bolts from the J30 to mount the front end of the thing up. The 2 stock 240 bolts ARE NOT LONG ENOUGH! good luck

[HashiriyaS14]

whoops im on my friends computer, im 2BN_S13. HAHA.

[trpower7]

Absolutely correct. Your speedometer will be about 4% off, at 100mph on your speedo you'll actually be going 104. The difference is neglibible. There is MORE than enough driveshaft slack to fit the J30 unit in; my car has been running like this for 2 years with no problems. You will need those bolts, or you could cut out that rubber bushing in the diff and use some washers to make it fit right. And swap out the rear covers. It takes me less than two hours if I'm working like a ***** to get the whole thing done from start to finish on an S13. Swapping housings, finding shims, etc, is a weekend professional job. Just put the J30 unit in with the S13 open diff rear cover.