George,
If the spring you posted a pic of is about 5/8", it probably came out of the input shaft seal. (hope I named it correctly) Here is a pic of the seal.
Here is a closer pic. Notice the shiny spring around the center hole.
As for the pin punches, I use "roll pin" punches. They work great.
The end of the punch has a rounded tit that keeps them centered on the pin. This helps especially when removing coiled roll pins.
Charlie has the fancy Starret punches. I couldn't afford those, and had to settle for the economy set.
Notice the tit on the ends of the punches.