24 hours with problem free gears. Hope it stays that way.

Im just concerned on how to break in the gears, and when should i have my oil changed for the new differentials? Because i have to take my car to the dealership for my 5000 km sevice check-up soon.

 

I had the FRPP gears installed and was told to just go through a few warm up cycles to make sure everything seated well, just a few short trips, as far as fluid I don't think you need to change it for the break in if that's what your asking. You should be good to go on that fluid.

 

I've changed gears in just about every car I've ever owned. I go a bit easy on the car for the first couple days, but then drive it like I stole it after that! I've even taken cars with fresh gears to the local dragstrip to flog the car. The fluid should be good for tens of thousands of miles (no "break-in" fluid change needed). I've never had a noisy or broken rear end to show for my methods.