Metal shavings And Super Low Temps

[yngbuck19]

The truck i have is a 1997 f250 auto E40D with 163000 mi. i just put a tranny cooler on it along with a tranny temp gauge when i took the plug out of the tranny for the temp sender for the gauge there was some metal shavings in the fluid the color was bright red with a little silver sparkle so that worries me a bit should i go ahead and flush it change the filter is it worth it to go with a bigger tranny pan thanks for any ideas in advance , Robby