I'm in the process of installing a Mike L. cooler, ATS deep tranny pan, and also flushing/change to synthetic fluid. When I went to change the spin on filter I didn't find a donut magnet in place with the old filter. My question is if people are generally installing these magnets or leaving them out, and if so, do the magnets just slip on the threaded filter mounting shaft?

The magnet is meant to be in place.

Magnet is a good idea. Pick one up at your local Allison dealer.
mike

Thanks HBruns, Mike L., that's what I suspected. A new magnet came with the replacement filter. I'll bet the old one is on the refrigerator at my dealers mechanic's house. It no wonder we do this stuff ourselves. Also Mike, cooler install is a breeze just like you promised. :)