That simply means that both units are now low on oil.

With that idea in mind, they do not realize thai once the gearbox has been filled and the thing has been run for a while, part of the oil has run back into the overdrive. One of the big problems we have with the Laycock overdrive is that people will fill the gearbox initially and not realize that it is somewhat difficult for the oil to work its way back in the overdrive unit.

So let us do a quick rundown on the things you can test, some of them not requiring you to have to remove the gearbox. So 99% of the time, if you can hear it energizing and it is slipping, it is something in the hydraulic system. When the pistons move forward, the actuating bar pulls two rods from the back and pulls the cone clutch in the opposite direction, activating the overdrive. The overdrive is energized by the simple fact of oil being picked up from the pump in the bottom through the screen, pumped through the system, through the control valve, and into two pistons about 1″ in diameter that are behind a device called an actuating bar. Normally speaking, if a car slips while it is in direct, it generally means that the spring pressure, for one reason or another, is gone (by the way, this is an extremely unusual situation), because the mechanical advantage always favors the direct drive, and consequently, the higher pressure and operating the higher pressure and operating conditions are needed for overdrive, or at least to energize overdrive. It tolerates very little internal leakage consequently, it requires very close control on the oil level in the gearbox. Unlike a regular automatic transmission, which works on relatively large volumes of low-pressure oil in the order of 50 or 60 psi, the Laycock unit operates on a very small volume of extremely high pressure oil at 400-500 psi. The overdrive shift is always controlled by hydraulic pressure. That is, the spring pressure you see when you put the gearbox and overdrive units together, created by eight springs. Direct drive is always controlled by spring pressure. The Laycock A-type overdrive is a two-speed hydraulically controlled planetary transmission.

Laycock j type overdrive oil