j30 diff problem

[s13coupe92]

so I got a 95 j30 diff in my s13 and its whined sence I got it. From my research the problem is the backlash is not within stock spec. When I add a shim how do I know if I've reached or exceeded stock spec? Also Ive heard it could be something to do with the spacers but idk exactly what that means...I last filled it with royal purple fluid, I don't remember the size I put in though but it made it a bit quiter.

[jspeedm]

you have to open it up and put some gear paint on the ring. rotate the ring while holding slight pressure on the pinion. check the contact pattern on the teeth of the ring. You should have contact right in the middle of the face of the teeth.

[s13coupe92]

ok so something new to add to this... i just looked at the diff and from the looks of it, it looks like a stock pumpkin.. it has the 6 bolt axles though. my guess is that its a early year j30 diff in the stock pumpkin. i cant really tell unless i open it up. idk if that matters though. ANYWAYS jspeedm what do i do to adjust it if its not in the middle of the teeth? is that wear adding a shim comes in?

[jspeedm]

a quick google and.....
Garage411: Nissan 240SX Differential Overhaul S13: cleaning, inspection, adjustments and more (http://www.garage411.com/DifferentialS13)

[s13coupe92]

wow that helps so much!! also made it seem so much more difficult.. lol thanks for the help man!! last question what gear oil do you recommend?

[91ka24]

When u put a j30 diff in you have to put the stock s13 diff cover on. That's why your cover is stock. as far as gear oil just use some synthetic 80w90

[titangts]

use any oil bro..it doesnt matter.. J30 diffs are viscous type. meaning there is a viscous friction oil INTERNALLY within the diff..

People are constantly getting this confused. They'll talk about how their diff seems to not lock up as good anymore and others will say, "change your diff fluid"..that wont fix a thing in a VLSD.. The oil in the diff case is only there for lubrication and cooling of the gears...Once the viscous oil goes bad, only thing you can do is shim it or change the diff..

[s13coupe92]

91ka24: I realize that but that's only the back plate. The diff housing seems to look like a stock diff housing.
Titangts: thanks man that helps