Atlas 23 spline input (Jeep & Dodge) & Jeep 26, JK's

JEEP & DODGE 23 SPLINE & Jeep 26

Stock Jeep transmissions 1980 & up with a 6 cylinder or larger engine were normally equipped with a 23 spline output shaft (except Peugeot). Since the Atlas was designed as a Jeep heavy-duty, low-geared transfer case replacement, it will bolt up directly to the stock Jeep transmission tailhousing that is equipped with the 23 spline output shaft. In these year Jeeps, the stock transfer cases used were both a driver's side (left hand drop) and passenger side (right hand drop) front driveshaft. The units listed accommodate both stock transfer case configurations.

Some of the later model Grand Cherokees with the A518, A500 & AW4 transmission will have some spline depth interference. On these applications, you may be required to use our spacer adapter P/N AS-0404. Failure to use this plate (when necessary) will cause damage to the Atlas.

The Atlas 23 spline transfer cases can be ordered in any low gear ratio offered for a 2 speed Atlas. The 4 speed Atlas is also an option for this spline count. These cases would use a STD. 23 spline input.


This automatic overdrive transmission was used in Jeep Wranglers from 2003 through 2011 in both the Jeep TJ & JK, and Dodge Dakotas 2004-2009. Both the 2 speed and 4 speed Atlas transfer cases use the short 23 spline input.


This automatic overdrive transmission is used in Jeep JKs from 2012 to 2018. The Atlas 2 speed uses a new 26 spline input shaft to couple to the A580 transmission. The Atlas 4 speed is not an option on the automatic transmission due to the computer programming issues on the Jeep drivetrain.


Jeeps with a manual transmission stayed with NSG-370 which is a "Short" Atlas 23 input and can use both an Atlas 2 or 4 speed transfer case.


The 45RFE transmission was used in 1999 to 2004 WJ Grand Cherokees with the 4.7 V8 and a NP247 transfer case. This transmission was also used in 2002 & newer Dodge Durango and Dakotas with a 4.7 V8. This transmission had a 1" recessed output shaft from the rear of the transmission. We offer the Atlas transfer case with a longer 23 spline input shaft to couple to the 45RFE shorter transmission shaft length.

Additional 23 Spline Transmissions:

The transmission output shaft length or Atlas input shaft length cannot be determined by transmission model only. The following are some transmission models that may differ from the 23 spline data:

1999-04 ZJ 4.7L - 5-45RFE NV247 stock transfer case (approx. 1" recessed output shaft)

Requires "Long" Atlas 23 input

2003-10 Ram 5.7L - 5-45RFE NV244 stock t-case (approx. 1/4" output shaft stickout with 1.55" spline) Requires "Short" Atlas 23 input

2001 Ram - 45RFE NV231 stock transfer case (approx. 1/2" output shaft stickout with 2.0" spline)

Requires "STD" Atlas 23 input & AS-8603

2004 Durango - 5-45RFE (3/8" output shaft stickout)

Requires "Short" Atlas 23 input

2005 & UP Manual Jeep 6 speed - NSG-370 23 spline Wrangler 4 cyl. & 6 cyl. transmission gear ratios of 4.459, 2.614, 1.723, 1.2, 1.0, .838 & R4.06 (output shaft approx .210" positive stickout). "Honsel" is cast into passenger side.

Requires "Short" Atlas 23 input

1" Spacer: P/N AS-0404 3/4" Spacer: P/N AS-8603 1/2" Spacer: P/N AS-8610


The Dodge NV4500 is probably the most popular Dodge transmission that we see coupled to the Atlas. Most Dodge 4WD transmissions are equipped with a 23 spline output shaft.

The Dodge 4WD NV4500 (1993-2000) has a 23 spline output shaft and has the correct tailhousing to bolt directly to the 23 spline Atlas transfer case.

Dodge also has a heavy-duty version of the NV4500 transmission that was bolted up to a Cummins diesel engine. This transmission, along with the 2001 & newer gas version NV4500 transmission, was equipped with a 29 spline output shaft. We offer an Atlas input spline for these heavy-duty and late model transmissions. (See the 29 Spline section for more information).