Addressing some engine and differential leaks
Do you know of a way to slow down or stop an oil leak on the differential of my front-drive 1985 Cadillac Eldorado short of complete disassembly. It has a factory replacement engine (1992) and that has several oil leaks also.
I do not recommend using any additives advertised to stop oil leaks because I do not believe they will work for you.
As to whether the differential needs to be completely disassembled to fix the leak; that, of course, depends on what exactly is leaking.
Some seals can be changed without complete disassembly so your first order of business is to determine why it’s leaking. This advice also applies to the engine— after you determine where the oil is leaking from you can formulate a plan to fix it. Or in the alternative, you can decide it’s not worth the effort and expense and just live with the leaks.