Seems the carrier break is the issue in this case.
Once you get past that, it helps to understand some of the basics for the diff you’re working on. Such as on the Dana 30, there is an oil slinger pressed on between the inner bearing and pinion head, and a baffle between the inner race and the housing. The baffle is usually 0.020” (that’s what all online sites list them as - it’s hard to measure the original since you destroy it upon removal…) and the slinger was a range, usually somewhere around 0.050-0.055, used to set pinion depth.
Aftermarket usually gives you a 0.030 slinger, so you need to reuse the old slinger or measure the old slinger and add enough additional shim behind the race to match that. Reusing the old slinger is probably not ideal because it was thick and set for the original gears depth, which is why the aftermarket thinner slinger so that you can dial in the depth with a stack of shims behind the race. So if using the new slinger and its 0.030, and the old was 0.055, you would put 0.025 behind the race at the 26:30 portion of the video you mentioned. The 0.030 would be under the pressed on pinion bearing. And of course you’d also use the new baffle from in the master kit. Not all master kits provide them, so you may need to buy some - Dennys sells them for like a dollar a piece.
A good starting point on the Dana 30 is a stack of about 0.070-0.075 total (sum of race shims, baffle, and slinger). I think I ended up at 0.074 on mine. If I remember right I started at 0.070, then 0.073, 0.076, then 0.074.
Not an expert or even close to it, just sharing some helpful info I’ve learned that can help waste less time.
I need more caffeine or less online time.