GM Service Manual Online
For 1990-2009 cars

Once the leak has been pinpointed and traced to its source, the cause of the leak must be determined for it to be properly repaired. For example, if a case component is resealed but the mating surface is damaged, resealing will not repair the leak. The damaged mating surface must be repaired or replaced. Before attempting to repair a leak, certain conditions should be checked for and corrected if necessary. The following conditions may cause a transmission oil leak.

       Important: The Suzuki 5-speed manual transmission does not use gaskets to seal major case components. GM P/N 12346240, or equivalent, should be used where applicable.

    • The oil level is too high.
    • A plugged breather vent.
    • Improperly torqued fasteners, dirty or damaged threads.
    • Warped flanges or mating surfaces.
    • Scratches, burrs or other damage to mating surfaces.
    • Insufficient or excessive amounts of sealer.
    • Cracking or porosity of the cases.
    • Improper sealant used where applicable.
    • Damaged seal bore.
    • Damaged or worn seal.
    • Scratched, nicked or damaged propeller shaft surfaces.
    • Loose or worn bearing causing excessive seal wear.