Gearbox Rebuild
Sensitively strip your modern classic’s gearbox and final drive
We show you how to disassemble your classic’s FWD transaxle.
The transaxle of a front-wheel drive car incorporates both a gearbox and a final drive. Most modern classics have a transverse engine, so the motion doesn’t have to be turned through 90° as it does with a longitudinal engine. This allows the gearbox to be compact and the final drive to be less stressed. Many use standard motor oil as a lubricant rather than extreme pressure (EP) gear oil.
The transmission’s main enemies are oil that’s never changed or checked and driver abuse, such as unsympathetic gearshifting or labouring the drivetrain in too high a gear. Even a well-treated gearbox, however, will eventually sound tired as the bearings
become worn, making their own noises as well as throwing the gears out-of-mesh and creating exciting gnashing sounds.
Our three-part guide will show you how to successfully dismantle, assess and reassemble a transmission that’s noisy or malfunctioning – or that’s simply an unknown quantity. Most front-wheel drive transmissions are similar in general architecture, but as usual you should obtain a workshop manual to provide specific data and explain the fine details of how to (and how not to) take it apart. Find out, also, what replacement parts are available. Seals are usually standard items, as are most bearings. Specialist suppliers will be needed for items such as synchromesh rings and gears, though most parts can be remade by engineering firms, at a cost. A factory manual may refer to special tools. A Haynes-type manual, meanwhile, will often explain work-around methods.