2004 Kia Rio

I have a 2004 Kia Rio that I bought with a bad engine. I just replaced the engine and got everything all back together and now I cant turn the engine over without a lot of force. Whenever I go to turn the engine over by hand with a wrench on the crank shaft it turns VERY hard and it sounds like there is scraping sound. The cars electric starter wont even budge it. I now took the transmission back off the newer engine and it is underneath the car. The engine is still hanging from the hoist in the engine compartment. Now the engine turns over fine without the transmission attached to it. What is causing the engine to turn over extremely hard when attached to the transmission. Keep the following in mind: I beat on the torque converter with a rubber mallett and tried prying it a little bit until I realized that I had to remove 4 nuts from the back of it to remove it from the old engine. I also did not do the following step stated below when I took the transmission off either time. Install SST(0K201 270 014) to prevent side gear from becoming misaligned.
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