Torque converter oil seal

[Bones]

I have a '78SC with a sportomatic transmission, after replacing the transmission recently a small oil leak led us to remove the engine and this showed us that the torque converter oil seal had 'popped out'. My theory is the seal was bad or was fitted with a bit of contaminant behind the seal, I didn't see as I wasn't there when it was fitted. Does anyone have any tips on fitting this seal or can recommend any seal glues that can stand pressure?