What would cause to a front seal to blow out? I just put in a used front pump with new seals, bearing and gasket. The pump came out of my other transmission that had a torque converter go out. After it was done it was dry as a bone only thing I noticed was a slight vibration in drive when stopped.

Would a bad or blocked pump (drain back valve) cause it? What about a blocked cooler line or backwards cooler line?

Anyone know which side of the radiator on a 95 E150 van is the trans return line?

I ask because I had to cut the lines and forgot to mark which was which but thought I guessed right and also heard it made no difference.