Once the leak has been pinpointed and traced back to its source, the cause of the leak must be determined in order for it to be repaired properly. If a gasket is replaced, but the sealing flange is bent, the new gasket will not repair the leak. The bent flange must be repaired also. Before attempting to repair a leak, check to be sure that the following conditions are correct as they may cause a leak.

Gaskets

1. Inspect to see if the oil level/pressure is too high.
2. Inspect for a plugged vent or drain-back holes.
3. Inspect for improperly tightened fasteners or dirty and damaged threads.
4. Inspect for warped flanges and sealing surface.
5. Inspect for scratches, burrs, or other damage to the sealing surface.
6. Inspect for damaged or worn gasket.
7. Inspect for cracking or porosity of the component.
8. Inspect for improper use of sealant, where applicable.

1. Inspect for a high oil level and oil pressure.
2. Inspect for a plugged vent or plugged drain-back holes.
3. Inspect for a damaged seal bore.
4. Inspect for a damaged or worn seal.
5. Inspect for improper installation of seals.
6. Inspect for cracks in the component.
7. Inspect for a scratched, nicked, or damaged manual or output shaft.
8. Inspect for a loose or worn bearing causing excess seal wear.