تسرب زيت ناقل الحركة

Fluid escaping from the transmission, lowering the level until pressure cannot be maintained. Low fluid is the commonest cause of almost every transmission complaint, so a leak is the thing to find before anything internal is suspected.

The symptoms follow the level: slipping under load, delayed engagement, harsh or missing shifts, all worse when hot and worse on gradients. The usual leak points are the pan gasket, the output and input seals, the cooler lines and the case connector — that last one also wicks fluid into the module's harness, which is a separate and expensive fault from the same leak. Check the level by the manufacturer's procedure, since most modern units have no dipstick and read meaningfully only at a specified temperature.