Any tips for changing differential lube?

This will be my first try at changing my differential lube. The year 2000 Jeep service manual I have says to use "flushing" oil to
clean out the case.
What's flushing oil?
I have the special friction modifier additive for the rear diff and Quaker State synthetic SAE 75w-140GL-5 and silicone sealent.
I was hoping I could cheat a bit and not remove the diff covers and pump out the old oil (suction gun) rather than break the existing cover plate silicone seal.
Any comments on this procedure please advise me.
Also how do I remove the old silicone sealent from the metal surfaces.

only makes the layer thinner but never actually removes the glue.
Any tips or tricks would be much apreciated I was hoping I wouldn't get lub running down to elbows like when I changed the oil in the manual transmission.
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For the first time, I recommend opening and cleaning it out to get any chunks of break in metal out. After that you can pump it out.
I have the best luck for no leaks with RTV 'sensor safe' silicone by leaving it to cure for the 24 hours like the directions say before filling them with oil. I use a razor blade for cleaning the old stuff, but you can get some spray gasket remover that is supposed to work well.
Note: You cannot use normal silicone anywhere near the newer vehicles. If the O2 sensors comes within smelling distance, they are dead.
Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's
greenjoytj wrote:

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