Gearbox limp mode article

Gearbox facts : Limp Mode

Raymond Uncategorized Leave a Comment


Most modern cars and SUVs today run on computer software. Take away the computer chips in the engine and transmission management systems, and the vehicle is just a useless heap of metal. Computers turn modern vehicles into superb works of engineering art, with every critical operation monitored by a sensor connected to the computer.

But what happens when the life-sustaining fluids (coolants, lubricants, hydraulics) or related mechanical bits in these smart cars go bad?

With age, wear and tear, components like radiators, hoses, gaskets, transmission and brake parts can become defective. If a sensor monitoring the engine or transmission functions detects a potentially serious problem, the management system may switch the vehicle into LIMP MODE. The kinds of conditions that may trigger limp mode include a low engine coolant fluid level, low engine oil level, or a problem with the transmission’s hydraulic fluid level, pressure or solenoid failure in the valve body.

The auto transmission uses pumped, pressurised hydraulic fluid to operate the various clutch and planetary gear clusters. If there’s a loss of fluid, a drop in pressure, or a failed solenoid, limp mode selects the most efficient undamaged gear circuit. It could also disable reverse and other gears, and reduce available engine revs, to allow the driver to reach an auto dealer or service centre instead of stopping on the road.

Limp mode is intended to help prevent catastrophic failure in the affected system, whether it’s the engine, transmission or other critical components.

Sometimes, a vehicle can switch into limp mode in error. The easiest way to check is to switch it off and wait a few seconds before starting it again. If it’s still in limp mode, you will have to try and drive it to a dealership or service centre, or a safe, convenient place where you can wait for a recovery vehicle.

It’s advisable to keep the phone numbers and contact details of several emergency roadside and recovery services in your phone contacts list, for this kind of situation. Many vehicle insurance companies provide emergency call centres for their customers.

Rex Diff and Gearbox provides a roadside assistance and vehicle recovery service for any vehicles suffering transmission or drivetrain failure.

Find RDG branches and contact us ONLINE!


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