At what mileage should the differential fluid on a 2003 G35 be changed?

I once read that the metal shavings collect inside and it's good to change it at 15k miles.

 

I did mine about 12k miles. It's been recommended as cheap insurance, and will reduce friction (albeit slightly) as a bonus.
Many here have done their's, and will continue to do it regularly and early.

 

Thanks for the reply, by changing it will it increase the transmission and engine performance?

 

It's cheap insurance to make sure that everything is nice and clean within the differential.

Use a nice 75W90 GL-5 synthetic gear oil. Right now I have Castrol gear oil in it but will be changing it to a different product in the next change. I just had some Castrol left over from the differential changes in the truck and wanted to use it up

You will need some new washers and a 10mm hex socket to do the work yourself. If your going to attempt it yourself be sure to read up on proper lifting and jack support locations.

 

The recommended Infiniti interval for the premium maintenance schedule is every 30K miles. But if you run your car hard more often or just want cheap insurance then every 15K is a good idea. Of course if your tracking your car many times a year you'll be on a much faster schedule.

 

here are two threads that should answer all your questions..

https://g35driver.com/forums/drivetrain/35247-rear-differential-oil-changed-must-do-read.html

https://g35driver.com/forums/drivetrain/35853-diff-oil-recommendations.html

 

It will increase performance, but not so you would notice . Someone suggested it would free up maybe a hp or 2.
But it's priceless for peace of mind.

 

The differential gear mesh is the highest single friction loss component in the drive train losses after the tire road interface [10%].
Diffs have tremendous low rpm [speed] losses but by 15-20 mph this is reduced to 2.5-3.5%.
Measure diff fluid temperature to determine the correct viscosity. Hard to fit a product that may see 0F cold and 200F hot on the same day........just like engine oil except the gear shear.

 

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Q45tech,
It sounds like it could be more than a hp or 2? What would you say, maybe 3 or 4?????

So by keeping rear diff oil fresh, it optimizes launch where you get the most friction?
Thanks for the tip.
C.

 

Mine will be changed to synthetic as soon as she comes out of hibernation. The trans is getting the synthetic treatment too.

Thanks for the advice and experience guys.

RBull

 

Does any one know what size washers we need to do a differential fluid change? I have a couple 10mm brass ones for oil changes, just need to know if I need something different. TIA

 

Any concern with factory warranty???
I thought Nissan / Infiniti didn't recommend synth.....????

 

I changed mine at 3500, then again at 45000. The mechanic said there was nothing on the magnet at all at the 45000. Been using the Amsoil Extreme Pressure https://www.amsoil.com/storefront/svg.aspx

Its a GL-5 rated gear lubricant. Dont wave the flag to your dealer "Look at me, Im using Amsoil, not OEM", but if it came down to a court fight, they would have a hard time proving that a GL-5 rated lube caused their design to fail prematurely.

I used synthetic gear oils in everything I own with a gearbox for years and have never had a single problem. I would like to use synthetic ATF in the G, but that is a totally different animal. Lots of strange stuff can happen in there. Electronic AT's are a complex beast, stick with OEM on those.

 

So when is a good time to change the VLSD fluid?

Oil or synthetic?

300 miles on car

 

I would change the LSD oil after the first 3K miles. Then every 15K after that. If you do that, it will last forever and you will never feel any slop.