Is an unplugged hole in the front drive shaft normal?

[FhPt]

When I connect a grease gun and add grease to the slip joint on the front drive shaft of my 94 JGC, the grease oozes out a small hole (about 1/10 inch) in the center of the front of the drive shaft. It is a type 1 front drive shaft (has slip yoke dust cap).

In the Haynes manual, it says to pump in grease until it oozes out around the collar. The grease never comes out around the collar though. It oozes out the hole in the frong of the drive shaft.

Is this normal? Seems like dirt and water could get in through that hole.

[jeepdwg]

Originally Posted by FhPt

When I connect a grease gun and add grease to the slip joint on the front drive shaft of my 94 JGC, the grease oozes out a small hole (about 1/10 inch) in the center of the front of the drive shaft. It is a type 1 front drive shaft (has slip yoke dust cap).

In the Haynes manual, it says to pump in grease until it oozes out around the collar. The grease never comes out around the collar though. It oozes out the hole in the frong of the drive shaft.

Is this normal? Seems like dirt and water could get in through that hole.

Yep it is normal and at least one constant since 1941.
dirt and water won't get in if it is filled with grease, but to your implied question of how to get the grease to go out of the collar you take your finger and plug that small hole while you are greasing and the grease should travel up the collar.

[FhPt]

Cool Thanks. It's good to know it is supposed to be there.

[JDPascal]

That hole prevents hydraulic lock on the slip yoke as the axle moves up and down and the shaft changes length. That would cause severe end thrust on the driveshaft and bearing problems

JD