741 pinion nut torque too tight- did i damage it

Needed to change the pinion yoke since one of the u joint strap bolts broke. Put a new one on and tightened it some with my electric torque wrench. Well I guess it tightened the nut way more than I realized. Threw the torque wrench on there and I over tightened it. Took the pinion yoke nut back off and started over. Now to get to just 200 # on the torque wrench the pinion will not turn. I thought the torque value on the nut was 240# and my electric torque wrench only puts up 300#. Any thought other than I shouldn't have put the electric torque wrench on it.