Vitamin C
Junior Member
- Joined
- Feb 14, 2023
- Posts
- 9
- Reaction score
- 18
- Location
- Holland, MI
- First Name
- Dan
- Truck Year
- 1974
- Truck Model
- C10
- Engine Size
- 350
Can someone tell me what the small square unit is that is installed between the factory speedo cable and TH350 transmission? It is on the tailshaft of the TH350 and looks to be some kind of reduction unit, the cable threads into it and it threads into the transmission. I am converting from the TH350 to a TH400 and was wondering what this is, and does it need to be used on the TH400 transmission?