Allright, I finally got it and maybe it will help you and others down the road.
First of all, a big piece of garbage.
In the back where you said there was a black tab, there is no tab.
On the back of the shaft there is a slot in the white plastic tab. You need to push the knob in as you said, insert a tweeker screwdriver into the slot (making sure you turn the knob so the slot is exposed) and you just pull the knob off (with a little brute force). Now the next problem is getting the setting part off. What I did was try to pry it off to no avail. I had to release the timer (slide locking, no screws) and pull. The escussion (or setting wash setting indicator) (do not know the tech. term) then flew off when I pulled the timer out.
Putting it back together is something of a mystery since the escussion has no "slot" to make sure it is aligned properly with the washing modes. I will be checking the new timer out soon and reply as to the settings if necessary.
Thanks for your help again