AT driveshaft greasing quirk

So i know that some may thing that i'm crazy. I can barely believe it myself. I decided to grease my driveshaft zurks points the other day. (It was a cold day and i did it outside) I filled all the U-joints till grease came out. Didyou something similar with the slip joint but i put a LOT in.

After that I drove to the Homeless Despot for some things, and when i pulled into a parking spot and placed my truck in 'park', i couldn't get my key out. The ignition wouldn't turn far enough to get the key out. That was because even though the truck's transmission was in park, the shifter lever was not totally in park. Totally new problem, never had it happen before. Finally figured it out, got my stuff, and drove home. Began to notice a new vibration in my heal near the gas pedal... thought to myself "oh crap, did i over fill the slip joint? Is that even possible? worried about if for 2 days while still driving my truck. Did a little research and thought that i might have to tear out my driveshaft and take some of the grease out. Well one day it warmed up and i had parked my truck in the sun. (Didn't plan it, it just worked out that way) and i came back out to my truck after work and drove away. I noticed the vibration had died out. When i parked , the trouble with the key had stopped.

The only thing i can conclude is that i had overfilled the slip joint which put extra pressure on the transmission and the shifter. When it warmed up and the grease flowed out the pressure on the tranny went away. That's the only thing i can think of anyway.

Thoughts?