u/CanadianBurger

Father/Son track days are the best.

Those are visits per day (not unique)

DTC-60 front, DTC-30 rear

Tools needed:
10mm hex (ideally a socket)
17mm socket
1 Liter bottle of 75W90 synthetic gear oil with a GL-5 or better spec.
Fluid pump (something like this:)
https://a.co/d/03h1GQWP

After jacking up and properly supporting the vehicle, locate the fill and drain plugs on the differential. The fill is a 17mm, and the drain is a 10mm hex. If this is the first time the oil is being changed, the plugs will be tight. Remove the fill plug BEFORE removing the drain plug. That way, if you can’t get the fill plug open, you haven’t drained the oil. Some oil may drain out the fill hole, so be prepared to catch it.

Remove the drain plug, and let the old oil drain out. It has a nice smell, so make sure you get a good whiff. JK, this is probably the foulest smelling fluid in the car. While draining, inspect the drain plug. It’s magnetic, and it’s normal to be covered in metallic gunk. Clean it thoroughly. Inspect the flat washer. It’s not a crush-type, and as long as it looks ok, you can reuse it. I’ve replaced the fluid a few times now, and never had a leak. Once the draining stops, replace the clean drain plug and washer and tighten to 36.9 ft-lbs.

The easiest way to add oil is to get a pump from Amazon or similar. It screws into the bottle and has a hose on the spout. Stick the end of the hose into the drain hole and pump new oil into the diff. It’s full when oil runs out of the hole. Inspect the fill plug and washer. Reinstall them and torque to 36.9 ft-lbs. Since it takes about 0.8 liters of oil, a one-liter bottle should be enough.

Clean up any spills or drips, and you’re done!

Very easy install

I was under the car installing the Perrin mechanical bypass valve, and just happened to notice one of the nuts was missing from the header on the right side. I replaced it, and while checking torque on the others, found the center nut on the left side loose by 15 ftlbs. These have never been touched so it’s odd both center ones were looser than spec, one enough to fall off.

I’d recommend checking these if you’re underneath.