It is fairl easy to change the differential cover gasket...
drain, remove cover, replace gasket, return cover, and fill w/ fluid... and your set to go.
note... be very, very, very carefull in loosening the diff drain plug and fill plug.... they tend to get strip pretty easy.... then the problem begins... damn fill plug head got stripped :x
be sure to get Redline fluid... not sure which one but it should be somewhere in the past post.... putting wrong LSD fluid on the toyota LSD tend to ruin the friction discs.... wolla LSD does not work no more
I've been through the pain of rounding the fill plug - some moron had tightened it to a million ft-lb and it just wouldn't come out. I ended up welding a big 17mm nut on the end of the plug, so I shouldn't have that problem again!