I was crawling around under the truck the other day doing the yearly greasing. The rear section of the drive shaft has a sliding section which was looking quite dry just behind the center bearing u-joint. I found the grease nipple for that area but when I pump the grease in it squirts out inside the u-joint while the sliding section remains dry. I would expect to see grease ooze out along the sliding parts but instead its almost like there is a direct path to the outside world from the grease nipple and the grease goes the path of least resistance. So it seems that no lubrication is getting to the sliding part. It does not seem right so do I need to investigate this further?

1950 3600
1951 4400
Gazz