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Your transmission with the 4.6L is a 4R70W. The 5.4L can be a 4R70W or a 4R100. As long as the trans is a 4R70W it will bolt up and plug in. The only difference between the 4.6 and 5.4 4R70W is the torque converter stall speed is slightly different, around 200 rpm. It is possible you will feel a reduction in torque.
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