per our website:

We also offer an install kit (Called Install Kit 1) which includes the basic parts needed for installation. This kit is all genuine Nissan parts, and includes pinion Nut, pinion crush sleeve, and pinion oil seal. Please note that in addition to the parts shown, there are also several sizes of side lash adjustment shims that Nissan offers. There is no way for us to determine what size(s) your car might need. The ONLY way to determine the proper size lash adjusters is during the installation by a competant installer. For those with higher mileage cars (typically over 25k miles) or who want additional peace of mind during the install, we also can offer the bearings as well as the bolts used internally (called Install Kit 2). Again, these are all genuine Nissan parts. Install kit 2 is sold separately from Install Kit 1.

 

So I just got my 4.083 final drive gears on my 07 HR but noticed that there is loud whine. When accelerating my oil pressure also rises to past 3/4 of gauge. Is this normal or anyone else experiencing this? As soon as I took he car out of he shop, somthing didnt sound right. When it went back in the shop, they said it was low on trans fluid. I think I'm going to take it back to them to check it out.

 

Just looked at some posts above and noticed that the diff wasn't done properly. Put about 50 miles on it, hopefully it isn't in bad shape.

 

Something doesn't seem right!!

 

Yeah, there should be no whine on accel, decel, or constant speed.

 

Got the car back today and it appears the whine is coming from a throw out bearing from when I did the slave cylinder recall. Taking it to the dealership tomorrow morning.

 

Maybe it was the muggy weather or maybe I'm just slow, but I got the car back after work yesterday w. my new 4.083's installed and didn't feel a huge change. I thought the difference was mild but probably perfect for my daily drive.

Anyone else feel this way? Maybe I just got my hopes up after reading the raving reviews of new found torque. I'm just itching for a faster car =/.

 

obviously no NA Z is going to feel lightning fast in 90 degree heat and 90% humidity. Even my own car gets a bit doggy feeling when its that brutal out. The difference is definitely there though, take it out at night, when the temps and humidity are down (tonight is probably not a good night though, supposed to be muggy as hell!)

 

Ya I mean I figured as much... I was just anticipating too much. I'd definitely reccomend going for 4.08's rather than the 3.9's if you are considering this mod. It's not going to be night and day. 4.083 is just right.

 

op:
i assume you had stock gears prior to going with the 4.xxx's. what where the stock gears you had when you made the 13.3x passes. i enjoy seeing another passionate enthusiast stay n/a. obviously the setup is good for 12's but have you added anything to make the 12" pass more tangible. i would like to see a dyno of one of your engines reving to 7200....i wonder how advantageous it is especially if your shift is coming just prior to 1320. you mind posting your shift points with old gear and current ones. im analytical and would be curious to know the answers to my questions if you feel you have it all figured out and my request are waisting your time...understood. good luck

 

UPDATE: The gears are still quiet and working very well. Very happy with them. Breakin was complete - So this weekend I changed the old breakin diff oil from Pensoil to Amsoil. There were metal shavings in the breakin oil, which I expected. Normal.

But - While I was under there I also noticed a very small 'leak' at the pinion seal. Not enough to drip, but there is a very light coating of gear oil on the front bottom half of the pumpkin.

Is that normal for re-geared diffs? It doesn't drip. Just a light 'sheen' of oil under the pumpkin. It also spun off the outer pinion assembly onto the undercarage a little....

 

Hey Gothgirl, I am not sure about the leak but I will tell you changing out the differential oil made the car drive about 100 times more better and smoother.

I wonder if that leak is normal....Need to see if I have one..

 

Yeah, I can live with it since it really isn't "leaking" that bad. I'll just keep an eye on it to make sure it doesn't get worse~ :-)

 

The guys who installed mine told me to drive normally and not worry about break in.. I havn't had any issues, but do you think that this puts the equipment at risk for failure? I'm glad I browsed this thread again because I probably wouldn't have change the diff fluid again.

 

technically should not leak - but given your description, not sure I'd even worry about it.

no break in needed in terms of the gears

 

Additional fluid change needed? Or is that only on full diff replacement

 

nope - same change intervals as the factory manual calls for. I only recommend doing a break in install when doing a diff too

 

I am still on the fence with either the 3.9xx or the 4.0xx fd's for my '06 Z. Getting the V2 motor installed now (oil issue), 15k miles, only mod is a drop in K&N. I dont track or drag, its just my daily runner. My driving is probably split 75town/25highway. Due to the cost, I am leaning towards the 4.0xx, but that 3.9 just seems optimum.

Damn choices, lol.

 

given the price, availability, the 4.08 is the one to get IMHO. Only a 4% difference from the 3.9, so the differences between them are nearly imperceivable.

 

+1