Transmission Oil Pan Inspection
After removal, inspect the base of the oil pan for debris and shavings. They can be an indicator of problems inside of the transmission. There are different types of debris commonly found in transmission oil pans.
Brass shavings: Gold-colored flakes found in the bottom of the oil pan indicate worn thrust washers and bushings. These parts are often made of brass and wear as mileage accumulates.
Metal shavings: Metal-colored shavings indicate chipped or worn gearset teeth. Remove any casting slag at the base of the pan on the first inspection of a new transmission.
Black pieces: Black pieces indicate worn clutch or band friction material. It is normal to find fine particles, especially around the magnet. Its job is to attract metal particles circulating in the transmission fluid.
Diagnosing Oil Pan Debris
This debris collects at the base of the pan and clogs the transmission oil filter. If a vehicle's transmission operates fine for a few minutes and then starts slipping, this debris is getting drawn into the filter by the transmission's oil pump.