did some welding now no start condition.
Ground is Ground. It don't matter where it was at.
Sorry no. Put this in your mind
You absent minded clamp the welder ground to the transmission.
Bear in mind that most STOCK cars have a poor (small) ground between the block and body, and the body is what you are welding on
So the "ground path" is
welding clamp..........transmission.......engine block........
.........and whatever it can find to the body
no 10 jumper wire from battery neg to body?
block to firewall bonding straps, small, 1 or 2 ea LOL
automatic, the cooler lines
and so on
NOW picture in your mind WHAT ELSE current might attempt to parallel through...................