This is an electronically controlled version of the "AXOD". 1991-1993 models had major reliability problems, but later models were less trouble. This transmission was renamed the "AX4S" in 1994 although it was still referred to as the "AXOD-E" until 1995. This was used on most Vulcans, all 3.2L SHOs (slightly different internals), all 3.8L V6s, and the 1991 2.5L I4. The 3.2L SHO versions has a different final drive ratio than the ones mated to the other motors. There is conflicting information as to when the production of the AX4S was stopped. Current research shows that it may have been phased out in early 2003 models.
The transaxle pan on this model will sometimes read "AXOD Metric" since it's based on the AXOD transaxle. This transaxle has 17 bolts to hold the pan on.
This transaxle was stronger and better than the "AX4S". It was used on all Duratecs and V8 SHOs and most 2000-2006 Vulcans. The V8 SHO version of this transaxle was slightly different internally (mainly different final drive ratio, higher stall torque converter, and more clutch packs) than the non-SHO version. Some 1994-1999 Vulcans got this transaxle although there was no reason why and they were pretty random. This transaxle is also known as the "4F50N".
The "AX4N" has a different pan than the "AX4S" because the two transaxles have different bolt patterns. This transaxle has 19 bolts that hold the pan on.