The GM TH400 main shaft kit is used when replacing a 700R4 in GM full size truck applications using the NP208 / 241 series transfer cases. Once installed into the TH400, the output side of the TH400 looks identical to a 4WD 700R4 that is being replaced. The adapter kit includes adapter casting, new TH400 output shaft, transmission dust cover, TH400 gasket, o-ring, dipstick and adapter instructions. 1986 and newer kit that has the short foot on the casting.
The GM NP 208 / 241 transfer cases are chain driven units with a cast aluminum case.
This adapter kit is designed for exclusive use with the 4WD GM TH400 automatic transmission. The TH400 has a case length of 24.250” and a “Texas-shaped” oil pan underneath it. The factory output shaft has a spline count of 32 spline and had various output stick-out lengths.
Note: Our adapter kit includes a new TH400 output shaft that must be installed into the transmission.