GM SM420 4 Speed Manual Transmissions to the 1980-89 Land Cruiser 19 Spline Transfer Case Adapter Kit

Our GM SM420 adapter to the Land Cruiser 19 spline transfer case is 4.00” in length. The adapter material is 356 T6 heat treated aluminum alloy. The adapter kit includes an adapter housing, adapter plate, 19 spline spud shaft, bearing retainer, bushing/gear locater, bearing, snap ring, set collar, gaskets, fastening hardware, and adapter instructions.

 

This adapter assembly fits August 1980 to 1989 transfer cases. The transfer case design was changed to a split-case design configuration with a 19 tooth internal spline on the input gear. 

 

This transmission works great in Land Cruisers. The overall length is 10-1/2”. It has the lowest 1st gear available of 7.05:1; 2nd 3.57:1; 3rd 1.7:1, and a 4th gear ratio of 1:1. The transmission was used in GM trucks from 1947 to 1968. This transmission has a 10 spline output shaft which we couple to using a new spud shaft. (Note: We have seen a few SM420 transmissions with a 32 spline output which we can also adapt to). The cast iron case of this transmission will sometimes require modifications due to interference with the front driveshaft or transfer case shifter linkage. A transfer case shifter linkage bracket is not included in any of these kits. As the years progress, it is getting harder to find this transmission and parts.