Not read a guide .. but it goes like this..
Position something to catch oil, undo fill bolt, some oil drains out, misses container. Clear up mess
Use something to syphon/drain as much oil from the sump via the fill hole as possible. Clear up mess
Loosen all the bolts holding the large sump on, then remove all but 4. Try and support the sump whilst removing the last 4, fail miserably and spill vast amounts of ATF all over self and drive. Clear up mess
Do the same for the small sump. Clear up mess
Clean the surfaces of both sumps and corresponding areas of gearbox of all traces of old gaskets whilst being dripped on by ATF from gearbox. Clear up mess
Remove filter and discover it holds about 1/2 ltr ATF. Clear up mess
Fit new filter, replace both gaskets and sumps. refer to
http://www.omegaowners.com/forum/YaBB.pl?num=1152783586on how to correctly refill gearbox.
Once car is runing properly, move from drive. Clear up mess
Use powerwasher/path cleaner/ swear words and fail to remove stains from drive. Throw all clothes in the bin. Stand in shower for 45 minutes with full bottle of washing up liquid in an attempt to remove ATF from hair, fail miserably.
Give up and get cold beer from fridge. Get large amount of static in ears from SWMBO.
Return to bathroom. Clear up mess