Reply to "DASH 1, oil volume"

One absolutely cannot drain all the lube out of a ZF without complete disassembly. I once had a ZF standing on a bucket with the case cover off, and when I separated the cases for gear work, about a pint splashed on the floor. Don't use the factory volume for casual lube replacemment: the 4.5 pint volume is only meant for dry, recently-overhauled ZFs.
Instead, fill as specified in the manual: add thru the side fill port until lube begins to drizzle back out the port. Then, go have a coffee or a beer, wait an hour and fill some more. There are dams, restrictions and passages inside that don't allow the 80W90 lube to flow away from the fill area rapidly. Over-filling will purge excess lube out the vent line when the ZF gets hot, making an unbelievable mess. Under-filling is worse: that will destroy your $10,000 transmission. So do it by the book.