So got the new 8" third member installed but something strange happened when adding the oil. It's supposed to take 2.5 quarts but when adding the oil it started pouring out of the fill hole early. I measured 2.5 quarts (80 oz) beforehand but it only seemed to take about 60 oz leaving a good 20 oz that didn't go in. I don't understand why I can't get all 2.5 quarts in. Worried there's not going to be sufficient amount of oil in there. No drain plug. Just a fill hole on the side. Any thoughts?
With the vehicle sitting level if lube is coming out of the fill hole, it's full. Don't try to add more, too much can cause leaks. If you installed it dry (new with no lube on it), spin it for few minutes to oil it then recheck.
Trapped air in the carrier? Doesn't seem like it would be that much if that were the case. Did you rotate it a few times to let it soak the whole carrier? Was it fully drained? Could axle tube sitting on an angle have retained some in one end? Are you sure on the amount required? I don't expect you measured what came out because who expects this? Online forums are saying FSM calls for "2 quarts or until it runs out of the filler hole".
The housing should have a vent which pre"vents" getting air trapped. The fill hole tells you when its at the correct level no matter how much it took to get there. I recommend adding a drain plug to the steel housing before putting the third member in. Saves a lot of mess if you ever need to drain it again.
I fail to see the difference between draining the differential in a drain pan by using a plug or draining it by backing the center section out a half inch ? What would be the motivation behind draining a rear end if it didn't have a problem ?
Maintenance? But that would require you to drive the car enough to need the oil changed, before having any other reason to disassemble the rear. Which I've done with Plan II. Glad the 57 Ford housing has a drain plug.
My OT brit sports car diff doesn’t have a drain hole, so I used one of those hand oil pumpers to get the old lube out. They must have wanted to save a buck on drilling and tapping the boss and didn’t think that the cars would last 60 years.
To me its simply a matter of convenience. Often getting the pumpkin separated from the housing doesn't always happen easily. Oil gushes everywhere including running down my arms and some always misses the pan and has to be cleaned up. With a drain plug, its a controlled flow and usually a lot less mess. Maybe I'm just a klutz when it comes to draining a rear end, but with a drain plug, even I have a difficult time screwing it up. Sometimes guys do have problems with their rear ends, and sometimes they change ratios to see what works best in their car. Normally its not going to be done very often, but when it does happen its nice to have a drain plug. Besides, I think they look kind of trick........one of those small details that looks like you put a little extra thought into a build.
Having a drain plug is nice if you're just swapping pumpkins, so you can drain the oil into a bottle, then use the bottle to refill the rear. I've done that many times, using only a small funnel to catch the oil.
When I was building the Stude I used a Dana 44 out of a later model Hawk, I don't remember the fluid being terrible...but it wasn't great. Later I got a Dana 44 TT (Twin Traction) out of another Hawk, when I opened it up the fluid was more like gelatin. I did lots of scraping and washing before I buttoned it back up. Both assemblies were over 60 years old and I assume had never been serviced.
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