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View Full Version : 180sx VLSD ... with J30 shafts?


Silverbullet
05-10-2005, 07:18 PM
hey guys, i've did some research and i never really found a straight answer. From what i read, ALL 6 bolt VLSD half shafts are the same. Now, here is my situation: I have a 180SX VLSD with NO half shafts. I also have a full 95+ J30 diff with the 6 bolt output shafts. Now, from what i read, these should fit right into the 180SX VLSD correct? Ok, so im having a problem, they dont seem to go in at all. Anyone care to explain or help me with their expirience? Main reason why i dont want to use the J30 diff is 3.9 final.

mbmbmb23
05-10-2005, 08:17 PM
As far as I know they should work but are side specific so make sure you are keeping them on the correct side. I would take the internals out of the 180sx pumpkin (to make things easier) and try to insert the J30 half shafts into it...to see up close why it's not going in. Maybe count the splines and see if they are the same.

ORRRR

Why not just swap the 180sx ring and pinion gear into the J30 unit.....that way you're still using the J30 VLSD unit (that the J30 half shafts plug into).....but the gearing is the 180sx gearing....like you want. I think it should fit....unless the J30 pinion is longer to account for the ABS sensor.

Anyone??



-m

drift freaq
05-10-2005, 08:33 PM
hey guys, i've did some research and i never really found a straight answer. From what i read, ALL 6 bolt VLSD half shafts are the same. Now, here is my situation: I have a 180SX VLSD with NO half shafts. I also have a full 95+ J30 diff with the 6 bolt output shafts. Now, from what i read, these should fit right into the 180SX VLSD correct? Ok, so im having a problem, they dont seem to go in at all. Anyone care to explain or help me with their expirience? Main reason why i dont want to use the J30 diff is 3.9 final.
here is the deal, with a 3.90 ratio your going to lose a little of your off the line punch . Of course this would not be noticable by the butt dyno ( hahhahahhahha) . It would only show up in 60ft times. Though the deal is like this if your running mad HP going to a 3.9 ratio can actually benefit you because it allows you to get more mid range and top end acceleration out of your car. Our cars were equipped with 4.08 gears for snappy off the line acceleration, thats why 180's and Silvias with SR's had them and its also why 240's stateside had them.
Thing is if you look at the larger displacement higher horsepower cars you will always see that Nissan as well as other automakers gear them higher. Now this may sound confusing but when its come to numerical gearing low numbers are considered high, because they make the cars top end higher. Vice versa High numerical numbers are considered low because they give you more bottom end or off the line acceleration.
With higher HP cars its common to see gearing anywhere from 3.36-3.90 , sometimes even 2.9 with big block american V8's. Usually anything below 3.90 is considered highway gears i.e. higher top speeds. vs drag or street gears which are 3.90 and up.
Most of Nissans larger Turbo cars and V8's ran anywhere between 3.54-3.70-3.90 . Back in the 70's the gearing was always a little more freeway gear oriented i.e. a 240z came stock with 3.36 gears . Of course it had a very torquey 6 cylinder in front of those gears. 510's came stock with 3.90's and had a whopping ( hahahhahha) 96 hp L16 engine stateside and a 110 HP L16SSS and 120HP L18SSS in Japan.
So basically in a nutshell you have laid out here the info to make a informed decision for yourself based on what your running power wise and what you want to do .
On the output shaft question itself yes you can put the J30 diff. output shafts in the 180sx VLSD they are both Nissan VLSD's from the factory and the output shafts are indentical.

mjjstang
05-11-2005, 05:43 AM
I know on 5 bolt they dont meet everytime, you have to skip every other hole and go to the next, Now I dont know if this is so with only having three different options of lining up (6 bolt) but try, or are you having other problems, I hope this makes sense.

infinitexsound
05-11-2005, 08:03 AM
use the j30 isnt much of a difference in gearing..
try switching the stubs.. just need to get past the snap ring part i believe...
3.90 isnt that tall compared to a subaru diff having a 4.11.. hmmmmmm

Silverbullet
05-11-2005, 09:58 AM
err i think u have it backwards... 3.9 will acel slower than 4.11.. anways....

heres the deal now. I counted the teeth. The J30s have 33 teeth... my so called "180sx" VSLD has about 29? I didn't even bother counting again because theres no i can miscount 4 teeth. So can anyone tell me what type of diff this is? Looks like im gonna end up using my J30.

orion::S14
05-11-2005, 06:17 PM
Recount...

J30 has 47 teeth on the ring gear...that's what detemrines the ratio.

47 too ring gear, 12 tooth pinion (47:12) = 47/12 = 3.916:1 ratio.

Stock is 49:12 (4.08:1)...many of the 180sx diffs are 48:11 (4.36:1).

So...recount, carefully. Or look for the #s stamped on the ring gear in XX:XX format.

- Brian

Silverbullet
05-11-2005, 10:19 PM
im talking about output shaft. not the ring gear.... i am not too sure where the ring gear is.

orion::S14
05-12-2005, 07:36 AM
Ahhhhh...sorry.

But FYI...The ring gear is the big one...pull the rear cover, it's the gear that's poking out.

[/no help]

- Brian

Janus
05-12-2005, 09:14 AM
The J30's year is important.

I think for the old VLSD's, you need 93 and older J30 outputshafts.

I'm not 100% sure on the specifics, you research it before you get new parts, but I know that you need the older shafts, for the older VLSDs

orion::S14
05-12-2005, 11:44 AM
^^^ But the spline count is the same for all S13/S14 open diffs, and all J30 diffs...regardless of the year.

You can slide S13/S14 open diff ouput shaft into any J30 VLSD...they just aren't long enough to make the viscous coupler lock the axles.

- Brian