The 231 came in many versions, so please be sure this is exactly what you need before purchasing.

The 231 (Command Trac) started coming in Jeep in 1986 in the Cherokee, Comanche and 1988+ Wrangler. The original read 231 AMC and was later changed to 231J, but they are the same case.

They had an enclosed rear output shaft up to 1995 like this listing. There is a separate listing for the 1996+ that has the exposed output shaft. These also had different input shafts. This listing is a 21 spline. It was used behind the 2.5 stick, and the early 6 cyl jeeps that had the Peugeot trans. Also used on SOME automatics. The other option is a 23 spline and that came in two different lengths. Another slight difference is the location of the 4x4 vacuum switch. Some are in the front case and others are in the back housing. If you have a preference on that, you will need to specify it. This style will come standard with a front yolk that is threaded for the U joint style drive shaft. It is good to have all the info off the circle tag on the back of the case before contacting us, because it will often tell us much of the needed information.