P0325 - Knock Sensor Circuit Malfunction - Could be a broken wire or bad sensor. Scan would let you see the sensor as you tapped on the block as a test. You could check the wire to see if it is broken but that' I about all without the test equipment.
P0420 - Catalyst System Efficiency Below Threshold (Bank 1) - Could be a bad O2 sensor or more likely the converter is starting to fail from age. Scan tool would let you run a test to see how the sensor is responding.
P0744 - Torque Converter Clutch Circuit Intermittent - The last one and your symptoms basically say the transmission ran low of fluid, got hot inside and burned the clutches and warped the steel plates. Also know as - time to rebuild the transmission.
The loud squeal and hard to turn suggest that the power steering pump is failing as well.
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Tuesday, December 20th, 2016 AT 4:32 PM