Maury spotted this one. It was on eBay (sold for $17.50). This 1979 guide seems a clever way to diagnose transmission problems.

“”Kaiser Jeep Corporation Automatic Transmission Circular Slide Rule Calculator” by the writers and illustrators of Kaiser Jeep Corporation, Toledo Ohio. No Copyright data; research indicates Kaiser Jeep used Borg-Warner transmissions at least 1970-1972 – probably longer. Here is a guide for use while servicing those transmissions. Kaiser Jeep published the wheel as a Mechanic’s tool, and as an advertising piece, for their dealers selling retail product in that era. Note – the photos you see are of this mechanic’s tool and advertising piece – no ‘Stock Photos’.

A tight firm clean double-wheel ‘slide rule’ calculator in tan/black, unmarked, a trifle darkened after a half-Century on a shelf. 7 1/4″ in diameter; the inner wheel is 5 1/2″ in diameter.

A guide to when service is required on these transmissions;
The order in which the tests should be made;
The reverse shows the Pressure Levels, where the Transmission selector (gearshift) should be place and what RPM or MPH should be utilized in those tests;
Speeds at which downshifts should be made.
A solid clean circular slide rule – lots of data on the reverse. Direct from a postwar Jeep dealer’s library. No mustiness, No smoke smell. We do try to describe them correctly – We want you back as a customer – hundreds of repeat customers. “