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Shackle Bushing

Insulated bushings to help prevent the transfer of noise and road shock from the suspension to the chassis and vehicle interior.

Shade-tree Mechanic

1. An amateur mechanic. 2. A mechanic with little or no knowledge of the trade. 3. A rural mechanic that literally works under a shade tree.

Shadow Graph

A scale using reflected light to indicate a difference in the weight of two parts.

Shaft Seal

An assembly that prevents vapor or fluid from escaping around the a rotating shaft.

Shaft-mounted Rocker Arms

Rocker arms that are mounted in a straight row on a shaft.

Shaker

A hood scoop on some muscle cars that channels directly into the air cleaner.

Shaky

A Chevrolet among Ford enthusiasts.

Shallow Staging

A term often used for back staging.

Shaved

1. A vehicle body with the factory chrome trim removed and the holes filled in and painted. 2. A cylinder head that has been resurfaced.

Shear Pin

A pin passing through two or more parts, as in securing a gear on a shaft, designed to break, preventing damage if an overload occurs.

Shelf Life

The useful life of electrical components when not in use.

Shell

1. Outer spark-plug casing having a threaded end and hexagonal flats for a wrench attachment. 2. Outer front and/or rear metal container of the power-brake unit. 3. The sheet metal body structure of a vehicle.

Shielding Gas

Protective gas used to prevent or reduce atmospheric contamination while welding.

Shift Forks

A Y-shaped component located between the low/reverse, first/second, and third/fourth gears on the main shaft of a transmission that causes the gear to engage or disengage via the sliding clutches.

Shift Kit

Parts required to provide high performance of an automatic transmission shifter.

Shift Lever

1. A lever used to change gears in a transmission. 2. A lever that moves the starter drive pinion in and out of mesh with the flywheel in some applications.

Shift Rail

A series of grooves in the forks to guide the shift forks, tension balls, and springs to hold the shift forks in gear, allowing them to interlock the rails to prevent the transmission from being shifted into two gears at the same time.

Shift Tower

The main interface between the drive transmission, a gearshift lever, pivot pin, spring, boot, and housing.

Shift Valve

1. A valve body component acted on by oil pressure, allowing fluid flow to the involved band and/or clutch at the appropriate time, causing the transmission to up shift or downshift. 2. A type of hydraulic valve, consisting of lands and valleys that resembles a spool for thread. The lands seal orifices and the valleys open them.

Shift Yoke

A term used for shift fork.