As soon as lube runs out of the fill hole, it is full.
Fill to the bottom of the "fill hole". When the fluid starts to drip out of the hole that you are filling in the diff, then you are full.
It is in the center of the differential cover.
You remove the differential cover to drain fluid. Reseal it with RTV, and fill with 80w90 to the bottom of the fill hole.You remove the differential cover to drain fluid. Reseal it with RTV, and fill with 80w90 to the bottom of the fill hole.
Usually you fill it to the bottom of the hole.
Pull out the fill plug, the level of the fluid should be up to the fill hole.
Remove the fill plug, pump or squease in lube until fluid comes out of fill plug hole, replace fill plug.
Through the check plug hole in the rear of the cover.
till it comes out of the fill hole about a quart
If you overfill an differential and it does not have a vent or the vent is plugged the oil, when it becomes hot and expands, will blow past the seals causing at a minimum a leak and at worst bearing damage. Always fill the differential to the bottom of the fill hole.
If you are working with a stock 10 bolt fill it until lube runs out the fill hole. If you are using an aftermarket cover where the fill hole is higher than stock, fill it to half axle height.
Recommended GL5 SAE 80W90 hypoid gear oil. Fill to bottom of fill hole.