I'm putting the finishing touches on my truck, and have a quick question. I put a allpro spool in the rear of my truck. Last night I filled the diff, the factory spec is 2.5qt, we'll I couldn't even get my finger in the oil from the filler hole. I went ahead and put the other half of the last qt in, and could touch the oil with my pinkey bent down in the diff. My question is this enough oil, should the oil run out of the filler hole when it's full. I figured when I installed it, that it didn't take up as much volume as the open diff, and would need more oil, but how much is my question . Thanks in advance for any help guys

 

My junk is spooled, and I've always filled it until it leaked out of the fill hole just a little.

 

I could be wrong, but I don't think a spool has the same volume as the spider gears do, there just isn't as much stuff in the diff anymore. So that would explain why you'd need more oil