Name that part.

[montana_hiboy]

How does the design lead you to believe it should be filled with lube?

Well the factory service manual for starters .....I mean no offense but i could'nt help but chuckle when you described the oil fill holes on the knuckles as "inspection holes" only ....that would be akin to calling the fill holes on your diff covers "inspection holes" only .......i mean yea sure you can take a peek inside but you're not gonna see very much through a 1/2" opening. Every guy's entitled to maintain his own rig the way he see's fit, but i have no doubt these knuckles were intended to be filled with gear lube.....

[basketcase0302]

Good stuff,

Most here in Florida will use grease instead of gear oil to help keep the water out of the assembly, (keep in mind we're constantly taking a "swamp-buggy" or truck through 4'-5' deep water where we hunt/ride). Agree with Average, they're a messy pain when you gotta service the assembly with that much grease in it!

Another bulletproofing "trick" I found years ago was to replace the "hollow" U-joints with the "solid" ones that have no zerk fitting, (not being hollow makes them a lot stronger). You can still shoot grease into them with the needle type attachment in the end of the grease gun

Basketcase

[4x4x4crewcab]

http://www.fordification.com/downloads.htm
The knuckle should have lube check out the link. Click on 1970 shop tips and then view the rear axle capacity section. In this it will mention the front axles on 4x4's showing the axle housing capacity and also having a footnote that says to add 1 pint to each knuckle.This same info is in the owners manual also P.51 The owners manual (or at least mine does) mentions the lube needed for the knuckle. P.49 Specifications,Lubricants,item Rear axles-all conventional--including 4-wheel drive front axle and hubs-----Ford Hypoid Gear Lubricant C6AZ.19580.B Some asked why the Ford engineers would design such a thing. I have seen this same system (closed knuckle) in Jeeps and 60's era 4x4
Chevys with Dana 44s so I would have to say it was the Dana Mfg. engineers that created this design. Good or Bad ? I won't give my opinion
either way but was it designed for oil? Yes, Is it better with Grease????
Is it better dry???? You decide we all know a bearing needs lube and this system pivots on bearings so regular maintenance of some kind should be performed.
Just my

[ICEMAN6166]

the info you speak of is in all the ford owners and shop manuals, jeep owners and shop manuals too.also in the chiltons and motors manuals.
i have had these front ends for years.
the design of the knuckles is Dana/spicers not fords.
i have always used gear oil, always replaced the seals and wipers and having never had any problems, will continue to do so.
thats my story and i'm sticking to it.