Triumph 2000, 2500 & 2.5Pi Overdrive
Laycock overdrive units transformed the Triumph 2000 series into relaxed motorway cruisers, reducing engine speeds by approximately 22 per cent in top gear. Two types equipped these saloons: earlier A-type units featured two-bolt solenoids and brass sump plugs, whilst later J-type overdrives used screw-in solenoids and rectangular finned sumps. These bolt directly to the four-speed manual gearbox, operating electrically through a column-mounted switch.
Overdrive Operation and Components
The hydraulic system engages through an electrically-operated solenoid valve, allowing smooth transition between direct drive and overdrive ratios. Oil capacity differs between types: A-type requires 2.0 litres total, whilst J-type needs 1.5 litres for gearbox and overdrive combined. Worn operating pistons cause slow engagement or complete failure. Clutch operation affects overdrive performance when hydraulic systems leak internally.
Electrical System Requirements
Proper ignition system voltage ensures reliable solenoid operation. Power flows through the differential speed sensor for safe engagement. Browse our complete Triumph 2000 series range for overdrive components.