Specifications

Small Hole transfer case (3-1/8”) Large Hole transfer case (4”)

1941-79 jeep & scout transfer cases

Small Hole Assembly Large Hole Assembly

1941-79 JEEP & SCOUT TRANSFER CASES

Dana Spicer 18 & 20 T/C and SCOUTS (1980 Dana 300):

Small Hole T90 Large Hole T86

This section of the Jeep manual deals with the 1941-1979 Jeep vehicles and Scouts. The purpose of this manual is to provide the

needed information to help you with stock part identification, conversion parts needed, and general information on what to expect

when dealing with drivetrain components. Along with that information, we have provided information on steering upgrade kits we

offer and the Saturn overdrive unit we manufacture. The information in this manual does change regularly, and we do recommend

that you contact our sales staff to verify anything that you may have questions on. No matter what you plan on swapping, Advance

Adapters can be your one stop shop for your conversion components.

These transfer cases, although used in different vehicles, all have the same bolt pattern. The only way they differ is the indexing

diameter when bolting to the transmission (referring to the Large hole T/C or Small hole T/C), and the input spline count on the transfer

case drive gear.

INDEXING: The Dana Spicer transfer cases were indexed

to the stock transmission by either a bearing or a bearing

retainer. Early Jeeps that were equipped with the T90 or T84

transmissions used a bearing to index the transmission to the

transfer case. We classify this transfer case as a small hole

transfer case. This small hole transfer case will require a

bearing when you adapt to this transfer case. In addition to this

bearing, our adapter will also require a thin bearing support

retainer. This support retainer is necessary to align our adapter

to the transfer case. This support retainer can be purchased

from us or be obtained off of a stock T90 transmission.

All other Jeep transmissions were indexed to the transfer case by either a retainer housing or an index hub which was part of the

stock transmission case. These transfer cases are classified as large hole transfer cases. Our adapters will require this indexing

retainer to obtain proper alignment. This retainer can be purchased from us or you can also use a retainer from a Jeep T86

transmission. All large hole transfer cases require this retainer. (Scout Dana 300s are also a large hole transfer case). When utilizing

either one of these retainers, we also recommend that a new 307 sealed bearing be used.

P/N 716002 - Small hole index retainer (T90) Dana 18 transfer case

P/N 716001 - Large hole index retainer (T86) Dana 20 transfer case

P/N 716302 - Sealed bearing (307)

Both retainers can also be purchased through a Jeep dealership and

the sealed bearing through a local bearing supplier.

SPLINES: All Jeeps and Scouts used a 6 spline input gear except the following applications: Years 1969 to 1971 Jeeps with

a T14 transmission used a 10 spline input. Jeeps with an AMC TH400 used a special 15 tooth drive gear. Scout transfer cases

used with an automatic were always 23 spline. (Note: On Scouts, we recommend you verify your input spline count before ordering

parts.)