Pat,
When the shaft seal leaks and allows water to get into the motor end it, it will corrode everything.
It does not matter if it is a saltwater pool or not...
There is a little hole on the bottom side of the pump, where the pump and motor meet. When you see any water under the pump, the seal needs to be replaced.
When this is not done quickly, then there is no repair possible.
Thanks,
Jim R.