Shim kit for the central lug detent on Tremec manual transmissions:

• Fits 1997-2019 Corvette w/ manual trans - all models
• All other vehicles - see separate listing

Includes 2 copper shimming washers & instructions

• Reduces effort to operate an overly aggressive aftermarket shifter; originally known as the "anti-venom mod"
• Option of using one or both washers (stacked) to adjust effort
• Requires lifting car off ground & working in a tight space with basic hand tools, but nothing else gets removed during the process & components are above fluid level

Background info (function of component altered by these shims varies by model):

• 1997-2004 (C5): This is the horizontal detent, which engages a groove on the central lug to provide a load that must be overcome to shift fore/aft into gear. It also defines a crisp horizontal neutral line for the shifter to follow laterally across the shift pattern without interference from the guide plate, and filters the transmittance of synchronizer engagement to the shifter. It is a spring-loaded device engineered for use with the stock shifter; with the reduced leverage of an aftermarket shifter, the force (at knob) needed to overcome this detent increases, making it more difficult to shift fore/aft into gears. By shimming this detent outward slightly, the force can be reduced back to a reasonable level.  Two stacked washers (~1/8") is the most one should install as this detent must still make contact to perform its function. On this model, the shim modification will NOT change lateral bias force as that is defined by a torsion spring attached to the front plate deep inside the trans.

• 2005-2019 (C6 & C7): The function and location of detents were changed in 2005 to be consistent with TR6060 / TR6070 rail architecture, specifically with changes to the central lug. The detent shimmed by this mod was "reappropriated" to become the lateral bias detent, which causes the side-to-side spring force you feel in the shifter. The horizontal detent and gear guide plate features were combined and moved away from the lug (no longer accessible to shim); however the lateral bias now defined by a ramp on the central lug is the first place to look for improvement anyway. With the reduced leverage of an aftermarket shifter, the force (at knob) needed to squeeze this spring increases, making it more difficult to access the off-center gates. By shimming this detent outward slightly, the force can be reduced back to a reasonable level. Two stacked washers (~1/8") is the most one should install as this component must still make contact to perform its function.

Softer reverse lockout spring also available