Atlas 21 spline input (Jeep)


The 21 spline Atlas was designed to fit Jeeps that were originally equipped with a 4 cylinder (and some 6 cylinders). Jeeps 1987 & up (with a 4 and some 6 cyl.) used 1 of 3 transmissions: the AX5, the Peugeot or AW4. The output shaft on these transmissions are either flush or protrude approximately a 1/2" from the stock transmission adapter. The AW4 transmission was most commonly found in the early Jeep Cherokees. All 4 cylinders manual transmission and most 4.0L 6 cylinder non-high output engines seem to be 21 spline transmissions; however, we recommend verifying the spline count on these transmission applications. The Jeep high output 4.0L 6 cylinder with the AW4 should be a 23 spline output shaft. NOTE: The 21 splines on these transmissions are very small in diameter, and thus we have seen the stock output shaft break on many engine converted vehicles.

When coupling an Atlas to these transmissions, the factory adapter is used. Due to the different output stick out lengths, vehicles equipped with a Peugeot and AW4 will require a 1/2" spacer plate to obtain proper spline engagement. In 1997, late model AX5 transmissions were changed to have an output shaft that protrudes a 1/2" from the stock tailhousing. Although this transmission can bolt directly to the Atlas 2 speed transfer case, we recommend using the 1/2" spacer plate for transfer case shifter clearance. This spacer plate should only be used on an AX5 that has a 1/2" output shaft stick out.

21 Spline Input For: Part Number: Transmission Shaft Stick out Length:

Atlas 2 Left & Right Drop: A21 .375"

Stick out length is the length that the shaft protrudes from the rear of the transmission with the adapter installed. The measurement is the length that the Atlas will accept.

1/2" Spacer Adapter: P/N AS-8610