Export vehicles may be different! In the USA, for 1975, Jeep CJ5 had either a T14, T15, or a T18 (four speed)

Since yours is a 3 speed, it is either a T14 or T15. To tell the
difference, the T15 is longer. Go to this page for a picture description of each:

http://www.advanceadapters.com/trans4179.html

You should have a Dana 20 transfer case with a single lever.

Is the vehicle a six cylinder or a V8 right now?