hello, i just got my car back with a nismo lsd and the central 20 final drive. the 3.9 one. and i was wondering if there is any type of breaking in that i need to do for any of these two? i really cant wait to see the difference from the final drive

Thanks

 

didn't it come with instructions?

there is a break in procedure for the Nismo diff... not sure of it, I am sure someone has a link though.

congrats, great setup you have!!

 

Instructions on the Nismo diff say to just drive it on the street like you normally do. Kaaz recommends doing figure 8s for 30 minutes their diffs.

 

well i drove around last night for about 100 miles but i noticed this huming noise when i am decelerating and im not sure what it is. does the lsd make noise or somthing?

 

anyone know if this is bad or am i just paranoid

 

I recently installed my Nismo LSD.

Here's what I did:

Did figure 8's for 5 minutes, drove the car normally for about 200 miles NOT accelerating around turns to keep the LSD from locking. Remember, you want the plates to rub against eachother so they have a smooth mating surface. Then right before changing my fluid for the first time I did figure 8's for 15 minutes. It works perfectly now. BREAK IN PERIOD IS CRUCIAL FOR LSDs! If you don't break it in, and just do donuts from the start, the lsd will NOT last. Trust me on this

If your LSD is humming, most likely its your backlash. If thats the case, you need to open the diff back up, and replace the shims that go between the carrier bearings. Any competent mechanic should be able to adjust it for you.
Also, I'd really recommend you take care of this as soon as possible because that sound is the gear teeth making improper contact. If you run it like that long enough, it'll wear out.
All in all, I'd get a second opinion, OR post a video of the humming on youtube or something.

The LSD should ONLY make noise when the clutch plates slip and grip and slip and grip randomly, in which case I'd recommend adding friction modifier (you can get them at ford dealerships, they work perfectly with most aftermarket differentials), OR run Motul 90a


Don't lose any sleep over this, just take care of it as soon as you can.


Good luck and post your progress

 

ok im gonna take it ot a local nissan dealer and have them look at it. ill post what they say

 

For anyone who buys that stuff: BE VERY CAREFUL NOT TO SPILL IT IN YOUR CAR OR GET IT ON YOUR BARE HANDS. IT'S THE WORST SMELLING STUFF YOU'LL EVER SMELL.

 

^lol that friction modifier. Hell yea it is. It was sealed in a plastic bag and my car still smelled. Now my living room does lol. God I can't wait to try the motul fluid when I change it this weekend.

 

Like the others have said, it sounds like you might have too much backlash in the ring and pinion.

How do you like the 3.91 gears?

 

they didnt make that big of a difference but i took the car back to the place that put it on and they told me that the final drive should make some noise but im still wanna get a 2nd opinion about it before i forget about it. but it defanently revs out a lot faster in all of the gears and it is really nice from a dig with the combination of the gears and lsd