'54 Buick rear diff. fluid

So I'm getting close to driving my buick, (it'll be the first time it's been driven in 30 some years.). I got the little plug off the diff to look at the fluid and it's BLACK... not much of a supprise, but now i'm wondering how to get the fluid out. There's no drain plug. I read my '54 shop service manual and it says, under NO cercumstances should the factory gear lubricaton be drained EVER. I have a hard time believing that. So I guess should I change it? If so, Best way to do it? Any suggestions on the type of fluid I would add? I'm pretty stumped at this point.

Thanks for the help!

 

I just looked in my shop manual, it gives you directions on page 1-9 to drain and clean the rear axle assembly. It's the last section on that page, I'm guessing you are reading the facotry shop manual I see the part you are talking about and the next section gives instructions on how to drain the rear end. It says just to loosen the bottom bolts on the cover and let the fluid drain out...

It also says to use SAE 90 Multi-purpose gear oil if you can't find and use the factory hypoid gear lubricant.

 

i would use my siphon pump with a long tube to suck it out

 

All right, I'll have to check that again in the book. I'll probably see if I can get some of thoes bolts loose, otherweise Siphoning would at least get most of it.

Thanks for the help.

 

if you take the cover off you'll have to make your own gasket or use Toyota brand silicone sealer( its the best out there) if you use mrGasket or any other over the counter gasket sealer it's going to leak......ask me how I know this !!