Product Description
TH400 automatic to Dana 20 adapter
It is not at all uncommon for the stock Jeep adapter housings to break in any number of areas due to the thin stock adapter casting. This strengthened replacement addresses this problem with a thicker, more robust part.
Made from 356-T6 aluminum, our reproduction of this adapter, Jeep #8624113, is thicker in all areas for increased strength. It is compatible with all associated stock components and will not require drive shaft length changes. Stock oil seals, gaskets, o-rings and bearing are not shown but are included and pre-installed.
This adapter is a factory replacement for the -1979 version found on the TH400 to Dana 20. This later AMC version case typically featured a slightly downward tilted / rotated rear flange, for which this adapter (like its factory predecessor) compensates for this to keep the adapter base level.
It is still usable replacing earlier TH400 factory adapters, but the rear mount foot will need to be shimmed with spacers, for which there is no engineering contraindication.
This style adapter is compatible only with the Model 20 transfer case. Though the Jeep Model 18 and 20 share the same bolt pattern, and in some cases the same bore size, this adapter is inappropriate for the non-direct drive of the 18 since its single ball bearing cannot support the moment loads offered by the 18's gear arrangement. Additionally, the availability of the correct 15 spline input gear for the 18 is essentially nil. See the interchange chart linked below.
