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Automatic Transmission Overhaul - 4L80-E: Maintenance GMC C3500 HD

Automatic Trans ~156 words

LUBRICATION

See appropriate AUTOMATIC TRANSMISSION SERVICING article in the TRANSMISSION SERVICING section.

OIL COOLER FLUSHING

  1. If available, fill line flusher with solution and install Oil Cooler and Line Flusher (J-35944) to top transmission cooler line on transmission. Follow manufacturer's instructions to flush oil cooler and cooler lines.
  2. If flusher tool is not available, flush cooler and cooler lines with a mixture of clean solvent and water. Flush cooler in both directions until all old fluid and debris are removed. If necessary, replace plugged or damaged cooler and/or lines.

Fluid Flowing Out Of Vent Or Foaming

Transmission overfilled. Fluid contaminated with antifreeze or engine overheating. Filter not seated. Cross-channel leak allowing pressure to leak in to vent area of pump cover.

Reduced Internal Lubrication

Cross channel leakage in pump cover. Pressure regulator valve stuck in high demand. Damaged oil pump mounting gasket. Stuck closed converter limit valve assembly (under heavy load).