John
You're experiencing the way they were. We used 90 weight and they were hard to get into gear when it was cold, but after a few miles, it got better.
If it was me, I'd invest in a synthetic lube that stays less viscous when cold. Should solve your problem. GM recommended that we do this in the 80's and 90's and it seemed to work.
I'd drain the oil and not waste too much time cleaning, unless it's really dirty. The odor seems normal. Fill the transmission up to the bottom of the fill hole.
If you decide to flush out the transmission, you might let it idle for a while, but I sure wouldn't drive it at all without porper lube in it.
