Ya may wanna change out the fluids & see what they look like. the goop that came out of my diff did not look like oil, it looked like someone packed the rear end with chocolate frosting about 20 years ago & called it good. Nasty stuff!
Lots of moisture in there, but thankfully there was enough oil in it to coat everything & keep the corrosion down. I'm still betting the abilities of that stuuf as a lubricant weren't real good.
Generaly a good idea to change all the fluids in any vehicle you're new to, ya never know when the last time they were done.

1956 GMC 370 dump " 'Tater "
1970 VW Volksrod "the Black Bomber"
2007 Chevy Avalanche
2020 Jeep Cherokee Trailhawk,
2005 Harley Davidson FLHTCUI

I dig all cars, old and new, whether they were hammered out of American iron, German steel, or Japanese tin cans. Being unable to appreciate them all is missing out on a world of great things.
But thats just MY opinion! :P