Shredded Oil Pump Gear - DNJ Aftermarket Pump Failure on 7M

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Problem

After a 7M engine rebuild, oil pressure dropped to zero after approximately 500 miles of break-in driving (under 55 mph), accompanied by a slight engine noise. Investigation revealed the oil pump drive gear teeth were completely shredded.

Oil pressure gauge reading zeroSlight engine noiseShredded/stripped brass oil pump gear teeth found on teardownOccurred approximately 500 miles after engine rebuild

Root Cause

The DNJ aftermarket oil pump has known tolerance and quality issues. The DNJ pump uses a serrated-type brass gear tooth profile (rather than the rounded teeth found on OEM and other pumps), which is prone to shearing. Multiple owners have confirmed DNJ oil pumps are mechanically noisy and fail prematurely compared to the OEM Aisin unit.

Confidence

High confidence — Multiple community members agreed on this solution

View Original Thread →Posted October 2023 on SupraForums.com