Checking the gearbox auto oil seals preventing oil leaks

Jack up the end of the car where the gearbox is fitted, and support it on axle stands. Chock the wheels remaining on the ground. Apply the handbrake if you jack the front end.Road dirt may hide a leak, so that the first sign you notice is a low gearbox level during a routine check.Checking the gearbox auto oil seals preventing oil leaks.
If the oil level has dropped, and you cannot immediately see the leak, top up then clean the whole gearbox with a proprietary degreaser. Drive the car a few miles then look for the leak again.
Usually a leak is from an oil seal, gasket or sealing washer. Damage to the casing is seldom the cause.auto oil seals.
The drain plug often has a sealing washer – if damaged it may leak. Examine all the inspection plates. Occasionally their gaskets deteriorate and cause leaks. The filler plug may leak because of a damaged sealing washer or thread. Check for a leak at the rear of the extension housing. It is usually caused by a damaged oil seal. Disconnect the prop-shaft and fit a new seal. On a front-wheel-drive car, check the seals at the drive shafts.
The drain plug often has a sealing washer – if damaged it may leak.Examine all the inspection plates. Occasionally their gaskets deteriorate and cause leaks. The filler plug may leak because of a damaged sealing washer or thread.auto oil seals.
Check for a leak at the rear of the extension housing. It is usually caused by a damaged oil seal. Disconnect the prop-shaft and fit a new seal. On a front-wheel-drive car, check the seals at the drive shafts.Checking the gearbox auto oil seals preventing oil leaks.
There are gaskets under inspection plates, which leak occasionally if the plate has been removed and refitted badly. Some plates can be reached only by removing the gearbox, a task best left to a garage. Other plates are more easily reached.Drain the gearbox oil and unscrew the inspection plate. Clean off the remains of the old gasket. Do not scratch the metal; scratches can prevent a proper seal being made later.
Smear both faces with gasket sealant and lay the new gasket in place. Refit the plate, check that the gasket is straight, and tighten the screws evenly. Refill with oil.A leak at the filler plug or drain plug is probably due to a damaged sealing washer. Fitting a new one should cure the leak.If it does not, the threads may be damaged. Making a new thread is best left to a garage.The oil seal where the speedometer cable enters the gearbox sometimes fails. Fit a new one .Checking the gearbox auto oil seals preventing oil leaks.
A leak at the front end of the gearbox may come from damaged seals in either the engine or the gearbox, or a gasket between the gearbox and the clutch bell housing. Such a leak often drips from the bottom of the bell housing.auto oil seals.
Such leaks must be repaired; if they suddenly get worse, severe damage could result. To replace these seals the gearbox must be removed – a job for a garage.On a rear-wheel-drive car check the rear end of the gearbox. A leak here usually comes from a failed extension-housing oil seal. You can disconnect the propeller shaft to renew this .
On a front-wheel-drive car, check the auto oil seals at the drive shafts for leaks.The gasket between the main gearbox and the extension housing is unlikely to fail, but fit a new one as a matter of course if you separate the two housings.Checking the gearbox auto oil seals preventing oil leaks.