A couple tips on filling aluminum differentials.
 

I just finished up servicing a couple differentials and thought I would share a couple things I have learned about filling the aluminum ones over the years.

1. I have started making a bung to weld into the rear cover just like cast iron rears had. I weld it into the cover at the correct level and then treat it just like the older ones. Aaron at Xtreme Motorworks makes one that also has a drain hole, but since the bungs are on the outside of the plate, it doesn't work for the supers with a factory style 3 point.

2. For rear ends that I have not done that mod to or if I just need to add a little, I use a large syringe and hose loaded with Hy-Tran. I can just stick the hose down the tube into the housing and squirt the oil in without the rear end burping up oil. This syringe will hold about 6oz. and I buy them for a couple bucks each at the local pharmacy.

Hope this helps reduce some headaches.

Here is another trick I have found. Cut a piece of 5/16" plastic air line tubing just a little longer than the length of the dip stick. Shove it in the outlet of a funnel and place it in the fill tube. The fluid will go down in the tubing and air will escape around the outside of the tubing. Fill until the funnel wont flow, lift up a little to empty the funnel and your done. Takes about 10 minutes for 2 gallons.

I used the plastic tube also. It did take a few minutes longer to fill but not one burp. I used the smallest plastic tube which was actually oxygen breathing tube that goes from the larger tube to the nose piece. I had a bunch of it and it worked great.

I use a pump I get from my AMSOIL dealer it looks like the pumps on condiments it works great.

The later tractors had a vent in the top of the case. On the older aluminum cases I drill and tap them for a vent. I use a small hose barb then run a hose to an inline filter. Makes filling them a snap.