Advance Adapters 50-0431A - Manual (Page 4)

SPECIAL NOTE: The components packaged in this kit have been assembled and machined for specific types of conversions. Modifications to any of the
components will void any possible warranty or return privileges. If you do not fully understand the modifications or changes that will be required to complete
your conversion, we strongly recommend that you contact our sales department for more information. This Instruction Sheet is only to be used for the assembly
of Advance Adapter components. We recommend that a service manual pertaining to your vehicle be obtained for specific torque vales, wiring diagrams and
other related equipment. These manuals are normally available at automotive dealerships and parts stores.
ADVANCE ADAPTERS, INC. P/N: 50-0431A
P.O. Box 247, 4320 Aerotech Center Way New Kit: (02/03)
Paso Robles, CA 93447 PAGE: 4 OF 5
Telephone: (800) 350-2223 Fax: (805) 238-4201 Page Rev. Date: 2-11-13
GM 4L60E TO NP231 TRANSFER CASES (21SPL)
upgrading to 95 & NEWER 23SPL.
On the inside of the transfer case, you'll now be able to remove the planetary assembly. Set the assembly on a work bench and locate the
snap ring that retains the input gear into the planetary housing. Remove the snap ring and lift the input gear out of the planetary housing.
INSTRUCTIONS for NP 231 input gear:
This new input gear will only fit the NP231 transfer cases. The installation of the gear will require the complete disassembly
of your NP231 transfer case. Since the transfer case has to be completely disassembled, this is also a good time to install
a short output shaft kit (fixed yoke kit) if you already have not done so.
If you've never disassembled a New Process transfer case, here are a couple of points to keep in mind that will make
the installation much easier:
1. Keep all bolts, nuts, washers, etc. separated into groups as you remove them. Make sure you keep them in a labeled
container that indicates what part of the transfer case they came from.
2. Keep all small parts in separate containers and label as to location and origin.
3. Make sure you have plenty of time and have a clean, spacious area to perform the installation.
Remove the front yoke nut with a 1-1/8" socket using an impact wrench. Remove the rear case bolts. A 10mm 12 pt. socket is needed for
the spline head bolt and a 15mm socket for the remaining bolts.
NOTE: The two black oxide finished bolts are located at the case dowel
positions and require a washer under them. Start to remove the rear case from the front case by
inserting pry bars at the cast-in locations
ONLY! Pry apart evenly to break the sealer bead along the
case mating surfaces. The front output shaft and chain should be retained with the rear portion of
the case.
On the front side of the transfer case, you'll need to remove
the 4 bolts that retain the aluminum bearing retainer. Once this
is removed, you'll find a snap ring that retains the input gear
to the cases' input bearing. This snap ring must be removed
so that the input gear can be removed from the inside.