Shim kit for the central lug detent on Tremec 6-speed manual trans found in:

• 2004-2015 Cadillac CTS-V
• 2016-2019 Cadillac ATS-V
• 2022+ Cadillac CT4-V Blackwing
• 2022+ Cadillac CT5-V Blackwing

• 1993-2002 Camaro - V8 only
• 2010-2024 Camaro - V8 only
• 2005-2006 Chevy SSR truck
• 2015-2017 Chevrolet SS

• 1992-2017 Dodge Viper
• 2004-2006 Dodge Ram SRT-10
• 2009-2023 Dodge Challenger - V8 only

• 2004-2016 Ford Falcon & FPV BA-BF, FG (Australian, V8 only)
• 2000 Mustang Cobra R
• 2003-2004 Mustang Cobra
• 2007-2014 Mustang Shelby GT500

• 1998-2017 Holden Commodore VT-VZ, VE-VF (Australian, V8 only)
• 2001-2006 Holden / Vauxhall Monaro (Australian, V8 only)
• 2001-2006 Chevrolet Lumina SS

• 1993-2002 Pontiac Firebird - V8 only
• 2004-2006 Pontiac GTO
• 2009 Pontiac G8 GXP

• Magnum & XL Tremec aftermarket transmissions

• Reduces effort to operate an overly aggressive aftermarket shifter; originally known as the "anti-venom mod"
• These washers install onto the hex "plug" located on right side of forward port near rear of main case
• 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 transmission model):

• T56 except CTS-V:  This is the horizontal detent spring, which provides 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.

• All TR6060 + CTS-V T56:  This is the lateral bias spring, which causes the side-to-side spring force you feel in the shifter.  On T56, this was in the shifter base, but got moved internally to accommodate cantilevered remote shifters.  To accomplish this, the horizontal detent previously located on the central lug is moved to the front of the case and combined with the gear detents previously defined by the guide plate under the lug; this detent is very difficult to alter.  However the lateral bias now defined 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