The "hole" in the dust cover is so fluids(water, oil, etc) won't gather in there, and get slung around by the flywheel. Depending on what kind of oil it is...if it is engine oil, there is a leak from the pan, the main seal, or even the rear of the intake.
If it is trans fluid, there is a leak at the front of the trans.
The P/S control valve can be cleaned with brake cleaner with no problems.
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Joel Adams
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