Advantek iron diff covers - which fill plug?

[Darel]

On the aftermarket Dana diff covers with two fill plugs, which plug is the correct one to fill to? Stock '21 JT Rubicon. I can't find any official documentation, but I did read somewhere that the upper plug is if it's high pinion and the lower plug is for low pinion, but I don't think there are different versions of this axle so I don't know why they'd make them that way. Thoughts? Diff cover in question:
https://www.northridge4x4.com/part/...HZW7dmgD3p8FijMat3BjmF7kg2OOgzgBoCSQoQAvD_BwE

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[Lunentucker]

Found this from Yukon
" High pinion refers to a housing where the pinion enters above the centerline. This is also called a “reverse-rotation” housing. High pinion housings are only found in the fronts of some factory vehicles."

 

[Darel]

Thanks, I know what high pinion is....just wondering if that's actually the point of the second fill plug or if that's just some garbage someone threw out on the interwebs.

 

[Panthers65]

SPECSHEET-JL-FRONT-UD44A-42019 (jlwranglerforums.com)

IF that doesn't link doesn't work look up the AdvanTEK® Front Axles spec sheet on dana's site.

Lubricant Capacity ...........
***Initial Fill: Fill to bottom of upper fill hole ........................................
***Service Fill: Fill to bottom of lower fill hole

 

[Jaxmax]

I have them on mine, use the lower hole, it measured the same as factory! I was gifted a set by a guy here “CrashEd” and sandblasted and repainted, and used permanent locktite on top plug and painted it when painting cover while other is black….Jack

 

[Darel]

Perfect, thanks guys! Wish I'd found that spec sheet earlier.

 

[Jaxmax]

I would fill to bottom of bottom hole as it would not be your initial fill from new or total rebuild. Mine were pretty rusted when I got them Crash Ed turned me onto “Steelit” stainless paint still holding up in NE salt on roads and the ocean beaches I frequent…Jack

 

[Darel]

We used steelit to paint the castings of the fillers we had at the brewery I used to work at. It's amazing stuff, even holds up to highly corrosive Monster Energy.

 

[Northridge4x4]

SPECSHEET-JL-FRONT-UD44A-42019 (jlwranglerforums.com)

IF that doesn't link doesn't work look up the AdvanTEK® Front Axles spec sheet on dana's site.

Lubricant Capacity ...........
***Initial Fill: Fill to bottom of upper fill hole ........................................
***Service Fill: Fill to bottom of lower fill hole

Yep, that is the way to do it.

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