A leak you cannot afford to ignore
An automatic gearbox relies on oil pressure to operate: it is what engages the internal clutches and lubricates the whole assembly. Even a modest loss can cause slipping, juddering or limp-home mode. Automatic gearbox oil is often reddish when new and turns brown as it ages.
Likely causes
- Sump or mechatronic unit gasket, underneath the gearbox.
- Output shaft lip seal, at the driveshaft or propshaft exit.
- Gearbox oil cooler hoses or fittings, usually at the front of the engine.
- Torque converter seal, between the engine and gearbox.
- Cracked casing following an impact.
Can you keep driving?
With just a few drops, yes — long enough to have the level checked, following the manufacturer's procedure to the letter: on many gearboxes, the level must be verified at a specific temperature and without a dipstick. With a significant leak, no.
Repair or replace?
Seals and hoses can be replaced without removing the gearbox, along with a top-up using the recommended oil. If the gearbox has been run low on oil and is now slipping or knocking, the internal wear is already done: a reconditioned automatic gearbox, tested and warranted for up to 24 months, is then the safe solution.
