6l80e to NP208 Adapter

Novak's 6L80E transmission to the Jeep Dana 300 or Early New Process (or New Venture) transfer cases conversion makes for one of the strongest drivetrain’s possible for both on-road and off-road, and has become an increasingly popular transmission to transfer case combination.

The Novak 6L80 to Jeep transfer cases adapter is compact at only 3-1/4" long for a combined transmission and adapter length of 26-1/2" (equivalent to a ~19-1/2" manual transmission). The adapter itself is machined of a 6061T6 billet aluminum alloy, featuring thick flanges and a heavy cross-section.

Advanced computer modeling methods were integral to the design of our 6L83 adapter assembly. We were able to push the bounds of product and process well beyond the status quo.

Our adapter is drilled for multiple clocking locations from near-factory (20 degrees down) to near-flat (3 degrees down). However, pan clearances and front axle width may inhibit the flatter options.

This transfer case adapter's design is based on Novak's Universal Series adapters that feature a modular mounting and support system. Included with the adapter kit is a steel base that is a highly configurable mounting foot.

Kit Includes: Billet adapter housing, transfer case input, transfer case to adapter gasket, fastening hardware, steel mounting base, and instructions.

There are two versions of the 6L80E transmission output shaft that will work with the Novak adapter. The stock 4WD version will work without modification to the transmission. The stock 2wd truck version will work with several modifications done externally. Other versions require the output shaft of the transmission be replaced and the rear of the unit sealed. All years of the 6L80E are compatible with the kits. 

The 4wd version 6L80E is ready to bolt up to our 6L81 adapter kit. Disassembly of the transmission is unnecessary as the 32 spline 4wd style output shaft which protrudes about 3" from the rear face of the 4L80E transmission main case is correct for this kit version. Disassembly of the transfer case is necessary to install a new matching 32 spline input gear.

The input shaft installation is a 1-2 hour bench job and usually includes either a simple gasket and seal replacement or preferably a full rebuild of a tired D300. Bearings and pre-load are involved with this job. It is not requisite that you rebuild your Dana 300 to successfully complete the conversion. However, it is certainly worth consideration especially if your transfer case leaks or has many years of service. 

The input gear installation is a 2-3 hour bench job and usually includes either a simple gasket and seal replacement or preferably a full rebuild of a tired transfer case, especially a chain replacement. It is not requisite that you rebuild your transfer case to successfully complete the conversion. However, it is certainly worth consideration especially if your transfer case leaks or has many years of service. You will be going all the way into the front of the transfer case to install in the input gear. 

Jeep New Process 208, 219, 228 & 229 Transfer Cases use the same output shaft style adapters as the Dana 300. Used in 1980 up full sized Jeep applications, they may be retained using these adapters and are fully compatible using the output shaft version. The simpler and more reliable NP208 can be a particularly worthwhile swap.

Our usual recommendation is to replace the older style transfer case (especially the troublesome 219, 228 and 229) with a newer, more modern version such as the part-time 231J with HD SYE kit installed and upgrades as appropriate. Also the 242 full-time case (particularly the AMG version as it is extremely strong) has the correct side drop and allows a mechanical speedometer output. Certain part-time Dodge 241 applications will also work. These more modern transfer cases allow the use of our cable shifter assemblies for a cleaner installation, have lower low range ratio, helical cut gearing, fluid pump, and are a newer more refined design. 

Because this is a longer transmission, it is not compatible with most short wheelbase Jeeps if they have much lift, due to drive shaft angles. CJ7's may be feasible if the lift is mild. However, CJ8 Scrambler Jeeps, other longer Jeeps, especially the FSJ’s are ideal candidates if punishing transmission duty is a prime consideration. 

Because of the complex nature of the communication between engine and transmission on these transmissions we recommend that the native engine be used with its matched transmission. The 6L series transmissions have an internal TCM (transmission control module) and take a signal via the can bus along with other inputs to calculate the best shifts and control. These units use clutch to clutch shifting on all but one of the forward gears and are extremely exact in their control. 

While possible, separate control of the 6L series transmissions is a complicated proposition and not something for which we provide support.

NOTE: WILL NOT FIT CHEVROLET NP208, only the Jeep version.

• Fits All with Late 6L80E Transmission (as noted above)
• Kit Includes: Billet adapter housing, transfer case input, transfer case to adapter gasket, fastening hardware, steel mounting base, and instructions.