Go to: http://www.caseih.com/
In right hand column, click "search for parts"
On lower right had column of new page, click "Begin your SEARCH for PARTS right here!"
This will open a separate window. Type in model number and click search. Select third open, 885 Selectamatic.
The numbers you are looking for are:
temp gauge AC Delco 7966282
sender, temp AC Delco 7966281