Adapting the

GM Muncie SM465

to the

Jeep Dana Model 300 and FSJ NP Transfer Cases

Our SM465 to Dana 300 conversion makes for a refined, broadly geared, and exceptionally durable assembly both on-road and off-road. It has become one of our most popular manual shift transmission conversions into Jeeps, providing a compact geartrain, a very low crawling gear, compatibility with excellent engines, and ease of installation.

The Novak SM465 to Jeep Model 300 transfer case adapter is compact at only 3.2" long for a combined transmission and adapter length of 15.2". The adapter itself is cast and machined of a high-grade aluminum alloy, featuring thick flanges, a heavy cross-section and strength-adding gussets. Because of combined length of this assembly, you are not likely to need to change your driveshafts if replacing an SR4, T4 or T5 transmission in 1980's CJ Jeeps.

<>Our adapter is drilled for multiple clocking locations. This will permit the installer to optimize the angle of the transfer case. However, shifters, clearances and other considerations may be limiting factors. This transfer case adapter's design features a modular mounting and support system and mounting base, ready to accept our industry standard urethane isolator mount, available in Related Products, below.

Any version of the SM465, including 2wd, 4wd early, and 4wd late styles are compatible with this adapter assembly and as such, there are two options to this transmission to transfer case conversion. Neither one method nor the other is any stronger than the other, so choose based on the installation factors discussed, as follows:

Option I: Early 4wd SM465 & Replacement Dana 300 Transfer Case Input Shaft

Adapter kit for SM465 to Jeep transfer cases

Kit 463-10, adapting SM465 transmissions (earlier 4wd version) to Jeep Dana 300 transfer cases, 10 spline input shaft

The 1968-1978, 4wd style SM465 features a 10 spline output shaft protruding 2-5/8" from the rear of the case and is compatible with this kit. Disassembly of the transmission is unnecessary. However, partial disassembly of the transfer case is required to install the provided 10 spline Dana 300 input shaft.

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 the Dana 300. It is not requisite that you rebuild your Dana 300 to successfully complete the conversion. However, it is a good idea if your transfer case leaks or has many years of service. See our select Dana 300 gaskets, master rebuild kits and upgrade components in Related Products, below.

This kit version is not compatible with FSJ New Process transfer cases. See below.

Kit Contents

  • Adapter housing
  • Transmission mainshaft with 23 output spline
  • Seal
  • Gaskets
  • Fasteners
  • Steel mounting foot base for crossmember mount
  • Instructions

Option II: All SM465 Versions & Replacement SM465 Main Shaft

Adapter kit for SM465 to Jeep transfer cases

Kit 463-23, adapting SM465 transmissions (all versions) to Jeep Model 300 & FSJ transfer cases, 23 spline mainshaft

All SM465 years and versions from 1968-1991 are compatible with this style of kit. A new, 23 spline mainshaft is provided, which splines directly into the factory Dana 300 and FSJ New Process transfer cases, with no internal modifications to these transfer cases required.

SM465 mainshaft replacement is required. These are somewhat technical rebuilds but good work is within reach of the careful home mechanic and instructions are included. We recommend at least our basic gasket & seal kit and the SM465 the main shaft bushing set. Better yet, this is a good time for a more thorough master rebuild and update of the transmission. See Related Products, below.

Kit Contents

  • Adapter housing
  • Transfer case input shaft, 10 spline / 30 spline
  • Seal
  • Gaskets
  • Fasteners
  • Steel mounting foot base for crossmember mount
  • Instructions
SM465 adapted to the Dana 300

Applications & Compatibility

sm465_with_463_adapter_rear_quarter_view

Compatible Jeeps

Compatible with most Jeeps that originally featured the D300 transfer case. If you are retrofitting both, keep in mind length and shifter location to ensure clearance for both. This combination may also work in early CJ's, though the floor tunnel may require rework. Wagons, Commando's, Full Size Jeeps, etc. are all good candidiates for this conversion. XJ / MJ Jeeps aren't as receptive to the SM465, given their tight tunnels and dash interference with the shifter.

Compatible Engines

Any engine that can be made to work with the SM465 will work with this conversion. They include:

Related Products


Urethane Rear Mount for Crossmember
SM465 mainshaft journal bushing kit
SM465 Gaskets Kit
SM465 transmission parts
SM465 transmission parts
Shifter Retention Kit, SM420, SM465, T176, NP435
Shifter stick for SM465
Shifter stick for SM465
Shifter stick for SM465
Shifter stick for SM465
SM465 Countershaft Billet Front Cover
Billet PTO Cover
1976-1986 Jeep floor tunnel cover
Dana 300 Rebuild Kit
Dana 300 twin stick shifter
Billet aluminum Dana transfer case pan
Dana 300 Super Short Tailhousing
Dana 300 Input Retainer Assembly
Turn-Key SM465

Installation Requirements

Tools

The transmission shaft installation takes more specialized tools, heavy snap ring pliers, a press to remove and replace bearings, etc. Normal mechanics tools are required for the balance of the installation.

Transfer Case Shifter

SM465 with Dana 300 twin stick shifter This transmission conversion will allow for the retention of the factory Dana 18 twin-stick shifters, Dana 18 single-stick shifter, and many of the Dana 20 shifters. Some tube-mounted Dana 20 shifters may need to be modified, or replaced with a twin-stick shifter kit. Dana 18 shifter clearance on some versions may require some grinding of an SM465 gusset for clearance.

If clocking the Dana 300 transfer case to a flatter position, removal of the second shifter mount ear on the 300 front retainer assembly will be required, as shown, whether for the factory single stick or the aftermarket twin stick kits.

Engines & Engine Mounting

GM Engine Mounts for Jeeps

Factory engine placement on CJ Jeeps is excellent for the SM465 transmission, whether using an AMC I6 or V8 engine. If installing an AMC or GM V8, your engine mounts should permit about a 1-1/4" offset towards the driver's side. Novak's engine mounts, feature vibration dampening, superior strength.

Driveshafts

Driveshaft length changes are often required. Most conversions to these transmissions will require that the rear driveshaft be modified to be longer and front driveshaft shorter. If you are replacing an SR4, T4 or T5 transmission, you can often keep your same driveshafts.

Some installers, concerned about the expense of new or modified driveshafts, attempt to let the existing driveshafts dictate engine, transmission and transfer case location, often to the detriment of the project. Our recommendation is to prioritize the correct position of drivetrain components over saving a few dollars which is usually regretted in the long run with compromised positioning.

Jeeps that require extensive travel or specialty-built driveshafts have this option available through several fabricators across the nation. These are normally specified after placement of the new transmission and measured at vehicle ride height. As the rear driveline gets shorter, it is often advantageous to us a Double Cardan or “CV style” rear shaft with the correct geometry at the axle to minimize vibrations and possible binding.

Axles

Use of factory axles is completely acceptable with this conversion. Axle upgrades are not necessary, but they may be chosen for reasons external to this transmission upgrade.

Also See

SM465 transmission with AMC bellhousing and Dana 300 transfer case