aw4 id

how can i tell if my aw4 is 21 or 23 spline? i know u need the 23 spline if u want to swap to a d300 which i would like to do. as of right now its still my daily driver and i dont have time to pull it apart and check like that. its a 88 aw4 mated to a np231 and 4.0.

kolby

According to this website: http://www.novak-adapt.com/knowledge/np231.htm

Your current transfercase has the short input for 21 spline. It was the same on my '88 w/aw4 and NP231, 4.0L

HTH,

Mark

87-90 AW4s are 21 spline, 91 and newer are 23 spline. The overdrive is .75 on the 23 spline version rather than .705 on the 21 spline. It's a direct swap to put in a 23 spline tranny (besides t-case of course) and you can usually buy an early 23 spline version for $200 or less.