Thanks everyone for the great information. I believe trying a penetrating oil may be a good idea and will try with WD-40. I have to admit I have not been patient and expected the engine to be unlocked in a few weeks. Now I have realized that whatever oil I use I will have to let it soak for at least a few months. Seems like my engine is froze up pretty bad, but I am 99.9% sure the engine has less than 175,000 miles and is still in good shape. Also, can anybody chime in about whether a suspension lift will prevent my 2WD C223 engine from working in a 4WD Trooper with it having the front axle and driveshaft in the way? I have heard of 2WD engines fitting into a 4WD chassis after one has lifted their vehicle and believe I can do it on my Trooper diesel.