In case anyone is interested, I did find this 17meg manual posted on the www.ab.com site! As it seems their site might be in flux, here's how to find the manual and other useful SLC related materials.
Go to www.ab.com site => support => online manuals and literature => then click on advanced search. Enter Allen Bradley in the Brand list, Programmable Controllers in the Products drop down list, and then enter '1745' in the publication number area.
This seems to be the only way to find some of the materials on ab.com The material will not come up under a search or otherwise.