[bandito2]

Yes, you >could< drain it by removing the final drive drain bolt on the underside and the oil check bolt at the rearward end of the drive below the shock. (and just a little bit forward)

The thing I used to fill it by forcing oil up the drain hole was a big syringe. You might be able to use something like a turkey baster. Service manual calls for 0.17 US quart = 5.44 ounces = 160.88cc, of #90 Hypoid gear oil but I think just saying 5 1/2 oz. or 160cc is going to be close enough. If it starts coming out of the check hole, then you've put too much in and should just let it run out til it stops dripping. That could take a while since the oil is fairly thick and takes a long time to flow. But that is also what makes it easy to change the gear oil without taking it apart. I injected a measured amount with the syringe and quickly covered the hole with a finger while I drew up a couple more measures of oil with my other hand then injected that from underneath as well and it was full with just a dribble coming out the check hole. Then I quickly replaced the drain plug bolt before too much oil oozed back out of the drain. I took a break for a couple hours while I waited for the check hole to stop dripping, after that replaced the check plug bolt and it was done.

That's the quick and easy way, but if you are ever in there to change the belt or some other drive line work and it's close to final drive oil change time, then it would only make sense to "Git R' Done" while the gettin's good. It's less of a mess that way. And it should be done with the clutch out of the way. You don't want any oil on that. And clean any drips in the case. Don't just wipe it with a towel.... use something like a bit of brake cleaner on a rag. Service manual calls for final drive oil changes every 2 years (no mileage is stated, just the time interval)

AND of absolute importance is to use SILICATE FREE coolant. Make sure of that. Coolant with silicates WILL RUIN!!! the water pump seal which is a bitch to change. It's a bit more expensive, like about 2X the average price of typical coolant , but I use the blue Honda TYPE 2 silicate free pre-mix coolant that I get from the Honda car dealership. There are other brands of automotive silicate free coolant for about half that price, but I am absolutely certain of the blue stuff being safe to use. Again, make sure any coolant you use is silicate free.