In that case, yeah, I'd fix it.

 

True, but selling someone a car when you know the transmission will soon give up the ghost - without at least giving them the opportunity to notice it themselves, if not telling them outright - is an A-hole thing to do and may come back to haunt you.

 

I am not sure if this is related to your problem but worth checking. I had my tranny rebuilt and they did not change the 2 pressure sensors afterwards. Two weeks later the tranny slipped from first to second gear. it was one of these pressure sensors.