Greasing the axle bearings on a rear Dana 44, and most other semi-floating axles, is a significant job.  The wheel and brake drum must be removed to get to the nuts securing the axle retainer plate.  After removing the nuts the axle can be removed with the bearing.  But the bearing is still partially blocked by the seal and retainer plate on the outboard side and by the bearing retaining ring inboard.  What that means in practice is that the bearing is greased prior to installation, and then ignored until it fails.  To promote longer bearing life, I came up with this modification.

The plan is to install a grease nipple in the housing between the bearing and the outer seal so that grease can be pumped through the bearing.  To give it a place to go, there is a relief hole next to the inner seal

This housing is from a ’74 Jeep CJ.  On some setups the backing plate is formed to come inboard over the top flat of the axle flange.  In that case this mod may require a different nipple or setting it deeper into the housing.

Here’s what needs to be done to the housing:

Note that the hole for the grease nipple straddles the interface between the outer seal and the bearing.  There is no gap there. The seal is pressed in by the retainer plate and it in turn holds the bearing into the housing.  That necessitates filing a notch in the body of the seal so that the grease can pass through.  The location of the nipple hole is obviously critical.  You should take careful measurements of your application and confirm where the hole needs to be.

The most common small threaded grease fitting has a ¼-28 thread and a 3/8” hex for turning it in, so it needs enough room around it for a wrench.  I didn’t want to give up that much metal, so I went with a press-in fitting.  It needs only a 3/16” hole.  It also has a 3/8” hex, which is unneeded for a press-in fitting, so I turned the hex round which lets it fit nicely into a 3/8” counter-bore.

Here’s what the machining looks like.  First make the counter-bore with a 3/8” center-cutting end mill.  Run the tool down just until a flat spot is created on the tube.

Then drill 3/16” through.  Center-cutting end mills leave a slightly convex face, so it’s good to first use a spotting bit so that the 3/16” bit doesn’t wander.

Here’s the finished grease nipple hole.

Then turn the housing over to drill and tap for the relief plug.  First create a counter-bore with a 7/16” center-cutting end-mill and spot-drill it so that the bit won’t wander.

Then drill the hole Q or 21/64” and tap it 1/8-27 NPT.  There are nice hex-socket plugs that will turn in flush with the housing.

Clean up the burrs inside and clean the housing thoroughly when the machining is finished.