Rear differential fluid replacement schedule - I35

[Borzoi86]

At what mileage should I replace the fluid in my '02 I35 rear differential?

Current mileage is 121K. (I don't see any record of fluid replacement in the car's records.) Car is driving fine.

I plan on driving this car until at least 200K miles.

Thanks!

[OwnerCS]

Isn't your I35 front wheel drive? The G35 is rear wheel drive, but the I30s and I35s that I've seen are front wheel drive.

Is your car manual or automatic transmission?

[Borzoi86]

Duh.

I had my other vehicle, a '52 Ford F-1 p/u, in my head.

Yes, my I35 is FWD.

(Is mine the dumbest post this forum has ever seen or what!)

Thanks for making me think straight.

[OwnerCS]

I usually just drain and refill my automatic transmission fluid over a flush. There should be a drain plug on your transmission pan. I've seen transmissions take on some issues after a flush. I usually change ATF every 30,000 miles. It may take 3 or 4 drains and refills over some miles to completely change out all of the ATF.