Speedo Housing GM Trans 1.935 Diameter 40-45T

The Speedo Housing GM Trans 1.935 Diameter 40-45T from TCI is a precision speedometer drive housing engineered for General Motors transmission applications, specifically designed for gear sets in the 40–45 tooth range. This component is essential for anyone rebuilding or modifying a GM automatic transmission who needs to maintain accurate speedometer function after a gear ratio change or restoration. Whether you're swapping transmissions, upgrading to a performance converter, or restoring a classic muscle car, a properly matched speedo housing ensures your dashboard gauges read correctly and prevents the typical "speedo creep" that occurs with mismatched components.

This speedo housing features a 1.935-inch diameter bore, machined to tight tolerances to accommodate GM transmission output shafts and drive gears in the 40–45 tooth configuration. The housing itself is constructed from durable cast iron, a material chosen for its strength and ability to withstand the rotational forces and thermal cycling of normal transmission operation. TCI engineered this component to pair directly with their transmission kits and aftermarket builds, ensuring concentricity and fit that eliminates wobble and binding. The precise 1.935-inch diameter specification is critical; even slight variations can cause speedometer inaccuracy or improper gear seating, which is why OEM-level precision in this housing matters for both performance and reliability.

Mechanics and transmission builders rely on this speedo housing when installing TCI performance transmissions, particularly in street machines, drag cars, and restorations where the original transmission has been upgraded or the vehicle has received a gear ratio change. This housing is compatible with GM transmissions using 40–45 tooth speedometer drive gears and will integrate seamlessly into TCI transmission assemblies. Proper installation requires careful alignment of the speedo drive gear to prevent noise and ensure consistent gauge readings; most installations are straightforward for experienced builders. At just 0.22 pounds and compact dimensions, this component ships quickly and integrates into your transmission project without adding weight or complexity.