Question

P0744 (Torque Converter Clutch Solenoid Circuit Intermittent). My 2000 I30 with 132800 miles- A - when drive in D mode the car only goes strong (normal @<2500 RPM) from 0-15 MPH. after that the engine rev goes up to 3500-4000 RPM but the car does not accelerate (still at approx. 20 MPH. Normally, by this time, the MPH should reach to30-35MPH), Then, the A/T shift into another gear with a strong jerk and the engine rev is still high @ >4000 RPM. in Drive D, the car could not speed more than 35 MPH.
B - When in Drive 2, the car drives Ok but at higher RPM as expected for towing heavy load. in this Drive 2 mode, the car can speed up to 45-50 MPH at 4000-5000 RPM. The shifts between gears are normal no jerks.
The transmission fluid was less than 10,000 mi when the AT acted up. Today, I replaced with a fresh AT fluid and the problem is still there. I notice that the old transmission fluid is little darker red not brown (burned) color. That makes me believed that the problem is either in the torque converter or in the valve solenoid or in the transmission computer module. The last is the gears and the clutches in the transmission box.
Any advice or help is greatly appreciated.