J30 diff???

[Srjustin]

I was going to get my open diff welded , then remammbered bout the j30 diff. Is the j30 a good lsd? I have herd its not the best and really not that great. So im kinda thinking bout just getting mine welded. What do you guys think?

[Srjustin]

So nobody knows much bout the j30 diff

[Captain]

a j30 diff is usually an lsd, you can shim an lsd to how aggressive you want it. a welded diff will be locked for ever or until it breaks. if you daily your car and dont have money to spend on tire every 4-6months then a j30 diff is the way to go.

[Edwin562]

J30 are not really worth the time & money. they dont always lock. i had 3 of them and they all acted the same.I did shim one and it preformed better. Saving up for a 2 way is worth the wait and money.

[KendallH]

I have a J30... it's decent. If you maintain it properly with regular fluid changes it can perform ok. A welded will suit you much better for drifting on a budget. But follow the 90/10 rule. Will you be drifting or daily driving 90% of the time? If its a daily, a J30 will adquately suit the 10% of the time you go drifting.

[ultimateirving]

i just shimmed and installed a j30 diff abotu 2 weeks ago. And i love it. got the dif for $70 bucks. Took it apart put the new shim and installed it. Whole procedure including removing the stock diff, took 3 hours.
It is awesome way easier to break the rear end loose.
if you can get a good deal on it. buy one, shim it, and you'll be golden

[h2v7]

i heard the j30 is about a quarter inch too long or too short and it will destroy rear main seals


is this true

[Srjustin]

Ok thanx guys and what do you mean by shim it?

[Jameskork]

I don't think anything having to do with rear size could affect a rear main seal since its not really contacting it directly. Idk though maybe it could push the internals of the tranny forward enough to push on the rear main seal. Halfway through this post I just became intrigued lol now I'm gonna spend all night trying to figure it out

[DaveAZ]

Originally Posted by Srjustin

Ok thanx guys and what do you mean by shim it?

Here is the article on shimming.

The J30 VLSD has an ABS sensor ring on the nose that adds about .75 inches to the overall length. About half the people on the internet say this requires a shorter driveline, (ABS) or it will destroy either the carrier bearing, or the rear tranny seal. The other half say that this is not an issue.

When installing these in S13's a lot of people are slamming up 1.5 inch washers to use for the front diff mounts. The S13 doesn't use the rubber grommets that the S14 and the J30 do, and if you don't hard mount the front of the diff, the rear S13 cover will break, as it is taking the torque load. (You do need the rear diff cover for your installation) We bought the aluminum spacers for the front mounts, since that provides a lot more stability.

Since our car isn't going to be tracked, we saw no need in welding a diff, or spending 15-1800 on a KAAZ. Welding is only good for smoking tires, bad for handling as a DD, and bad on tires. So for us, the VLSD was a logical choice. We'll start the installation in about an hour. There is a lot of info on this, and most of it contradicts itself, so I guess in a couple of hours, we'll know. If we have driveline issues, we'll get an ABS single.

[h2v7]

college student DD weld job holler

[Kingtal0n]

whats wrong with a typical VLSD from a 180sx? Usually they run about $200~

[KiLLeR2001]

J30 is way better than an open diff. I can confirm that.

[zooopreme]

Depends on the sealed unit inside the pumpkin. You could add the best differential oil in the pumpkin and still have a crappy diff because of the sealed unit.

From my experience, if the vlsd's sealed unit is crap. The diff is crap.

[DaveAZ]

Originally Posted by Kingtal0n

whats wrong with a typical VLSD from a 180sx? Usually they run about $200~

Because unless it's an 88-90 180SX, (rare now) you'd also need the axles?

Instead of getting a 95-96 diff out of a family car, you'd be installing a hotrodded 20 year old diff that needs a rebuild? That was my rationale anyway.

(Edit) Just put a J30 VLSD in today. My son corrected me and said that his 1993 180SX had VLSD and six-hole axles. I try not to BS in the threads, so wanted to toss that in there.

Another post I had concerning which diff we had here.

[laurentj23]

Ok guys. I dont wanna make a whole new trade about this. But i managed to take the diff apart and screw it up when i tried to shim it. I know. Give me hell. Where can i found a manual to assemble it? I look at the fsm and its not helping at all? Or where can i take it to?

[5280VertDET]

Originally Posted by laurentj23

Ok guys. I dont wanna make a whole new trade about this. But i managed to take the diff apart and screw it up when i tried to shim it. I know. Give me hell. Where can i found a manual to assemble it? I look at the fsm and its not helping at all? Or where can i take it to?

http://zilvia.net/f/showthread.php?t=200226

Also any differential shop should be able to help you out.