Advance Adapters 50-6802 - Manual (Page 2)

GM TH350 AUTOMATIC TO NP231
TRANSFER CASE (23-SPLINES)
ADVANCE ADAPTERS INC. P/N: 50-6802
P.O. Box 247, 4320 Aerotech Center Way Old Part No: 711068-23
Paso Robles, CA 93447 PAGE 2 OF 3
Telephone: (800) 350-2223 Fax: (805) 238-4201 Page Rev. Date: 01-23-12
SPECIAL NOTE: The components packaged in this kit have been assembled and machined for specific type of conversions. Modifications to any of the components
will void any possible warranty or return privileges. If you do not fully understand 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 values, wiring diagrams and other related equipment. These manuals are normally
available at automotive dealerships and parts stores.
GM TH350 3 SPEED AUTOMATIC
The General Motors TH350 has a case length of 21-1/2", 13 bolts for holding your oil pan in position and is available in two different
engine to transmission bolt patterns. The case is available with a Chevy bolt pattern that has the top two holes 8-1/4" apart or
in a Buick bolt pattern that has the top two holes 7" apart. The rear side of the transmission case should have a square bolt pattern
that uses 4 bolts. There are several various lengths of output shafts that these transmissions have been furnished with and you
will be required to disassemble your transmission for use with the new shaft provided. The new shaft will have 23 splines that
will engage directly into your transfer case. The speedometer gear is normally located in the tailhousing but, when adapting it
to the transfer case, the location will change to the back side of the transfer case. The rear transmission support is located in the
main case just forward of the tailhousing connection. This can be used for supporting the crossmember on some installations,
but most of our kits provide support on the new adapter housing.
When installing the new transfer case adapter, make sure that the input gear and the output shaft do not bottom out. We have
found on occasion that a transmission output shaft may be slightly longer than we have allowed for. The adapter housing and
transmission output shaft must be assembled to the back of the transmission without interfere.
DO NOT FORCE THE NEW
TAILHOUSING ONTO THE TRANSMISSION. If assistance is needed, please feel free to call the number listed above.
When assembling the adapter housing to the transmission case, we have provided you with a new square-type "O" ring seal to
prevent fluid leakage. This seal is a stock GM item that is used on all TH350 installations.
If you have selected a transmission that has the old style modulator, then we recommend the use of the Advance Adapters
adjustable modulator Part No. 716010. This will also allow for additional driveshaft clearance.
All installations will require the use of a transmission cooler. The cooler can be either installed in the radiator or a remote location
is acceptable. The transmission shift control can either be a Hurst floor mounted type shifter or sometimes the existing column
shift can be modified on certain applications.
This adapter kit was introduced in August of 1990, for use on the Cherokee type vehicles that were replacing the 999 automatic
transmission. The adapter is 1-1/2" thick and will provide an overall transmission assembly length of 23". This length is will be
very compatible with the Wrangler AX15 and Cherokee type vehicles replacing the automatic 999 transmission.
The adapter crossmember support is designed around replacement of a AX5 Cherokee manual transmission. If you are replacing
an automatic transmission, you will find that the crossmember support will hang too far down when it is bolted to the bottom of
our new adapter housing. On Wrangler conversions, the crossmember support can be easily adapted to the original rubber. On
Cherokee conversions, it may be necessary to purchase a new crossmember that was used on the manual transmission
applications.
The transfer case linkage will require the fabrication of a new support bracket.
Two rotations are provided on the casting. Choose the rotation that best suits your application.
Two of the positions on the rotation will require removal of two studs from the transfer case and substitution by the two 3/8"-
16 x 1-1/4" Socket Head Cap Screws. This is due to lack of wrench clearance around the casting.
Use silicone sealant on both sides of the transfer case gasket. Use Loctite on all bolts.