History on the problem. Few years ago my friend was having trouble with lock up under WOT. Locked great normal driving (Precision 5 disc). He had a billet trans built --installed the convertor on the new trans and it worked great for a while until clutches in convertor burnt. Convertor rebuilt and has worked good for a couple years or so. Sent convertor back for freshing again. Just installed and the problem is back. This 2 different trans. It locks hard @ cruise but going by DS it tries to lock but @ the top of 3rd but only a couple hundred rpm drop--not 800 as it should be. Locking with chip or manual switch--same results--must find problem or clutches will be burnt in short order. 1 ? is the solenoid seeing greater pressure against it @ WOT as compared to light throttle? We know the trans has or did have great line pressure. Is there any way the solenoid could be seeing reduced voltage? Open to any and all ideas.