version uses a larger 1.375 outer diameter output shaft for higher capacity and a longer rear case.' The Volvo version kept the same package size as the J-type but with the updated 18 element freewheel and stronger splines through the planet carrier. The P-type overdrive marked the last updates and included both a Gear Vendors U.S. The J-type overdrive was introduced in the early 1970s, and was adapted to fit Volvo, Triumph, Vauxhall/Opel, American Motors and Chrysler motorcars, and Ford Transit vans. In 1959, the Laycock Engineering Company introduced the D-type overdrive, which was fitted to a variety of motor cars including Volvo 1s, Sunbeam Alpines and Rapiers, Triumph Spitfires, and also 1962-1967 MGBs (those with 3-synchro transmissions).įrom 1967 the LH-type overdrive was introduced, and this featured in a variety of models, including 1968-1980 MGBs, the MGC, the Ford Zephyr, early Reliant Scimitars, TVRs, and Gilberns.

Later the A-type overdrive was to be fitted to the entire range of TR cars. Several famous marques used A-type overdrives, including Jaguar, Aston Martin, Ferrari, Austin-Healey, Jensen, Bristol, AC and Armstrong Siddeley. The first unit to be created was the A-type overdrive, this was fitted to many sports cars during the 1950s. 'The first production vehicle to feature the Laycock system was the 1948 Standard Vanguard Saloon. Been a long time since I have posted (but reading a lot) on here as I have been driving the car not tinkering with it too much.Īnyway I have been fiddling and I hope this may help someone outĪs one or two of you may know I was having overdrive problems just before the last 10CR and tried (unsuccessfully) to fix it at the time.Īfter the run when it gave up completely I started to look around for a replacement unit and found this info on wikipedia,

Laycock j type overdrive for sale