Summerfi,the zerk on the top rear of the trans is not for grease it was originally put there for quick filling the u-joint at the factory during assembly,it would be best to replace it with a plug so as not to accidently grease it.With the torque tube in place, with the cork seal, that front u-joint is lubed by the transmission oil.
Terry


'52 Chevy 3600
'03 Chevy 2500HD
'64 Pontiac Grand Prix
'93 Jeep Wrangler