Advance Adapters 50-3100 - Manual (Page 2)

GM TH350 AUTOMATIC TO
JEEP & SCOUT DANA 18/20 1945-79
ADVANCE ADAPTERS INC. P/N: 50-3100
P.O. Box 247, 4320 Aerotech Center Way Old Part No: 711031
Paso Robles, CA 93447 PAGE 2 OF 3
Telephone: (800) 350-2223 Fax: (805) 238-4201 Page Rev. Date: 10-12-14
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
The General Motors TH350 has a case length of 21-1/2", 13 bolts for holding the 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 the transmissions have been furnished with and you
must make sure the proper shaft has been installed into the transmission for use with our transfer case kit. When overall transmission
length is critical, we standardize on the GM 4WD output shafts that were used in vehicles 1973-79. If the transmission you purchased
has the correct output shaft, you can return the new output shaft for credit. All TH350 output shafts will have 27 splines. 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 coupler 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; and when coupling into our new
spud shaft, we find a small amount of interference. The adapter housing and spud shaft must be assembled to the back of the
transmission without interference.
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
On most installations, a pan modification will be required for clearance of the front Universal yoke. On early model Jeeps up to
1965, it may be necessary to change the front transfer case yoke to the smaller design (from a 1966-1971 Buick V6 application). For
additional front driveline clearance, we recommend that the engine and transfer case be offset to the driver's side approximately
1" of centerline. This offset will help the front driveshaft clear the TH350 oil pan.
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 is supplied with a special set screw, Part No. 724319. It is to be used on Dana 18 transfer cases that have the dual
shift lever type transfer case. The set crew will replace the square headed bolt that is used on the inside portion of the shift handle
mounting. By using the set screw configuration, additional clearance can be obtained.
CAUTION: This adapter is not to be used with a GM 700R-4 automatic overdrive transmission. The adapter length is not long
enough to allow for front driveshaft clearance when using the Jeep Dana 18/20 or Dana 300 transfer cases.