I'm about to throw in my strange 12 bolt with the preload cover. I had some of the fluid come out, not sure how much, when I had it upside down for painting. So I have to add some fluid, do I fill it up till it comes out of the fill hole on the cover??? This is true for the stock rear but the directions say to fill it with 2 quarts gear oil and 1 bottle GM additive(however, mines not empty and i don't know how much is in there). Will I over fill it by filling to the top?? I added about half a quart already, and it looks to be about 1 inch below the fill hole and I am pretty sure I didn't lose that much.
Please let me know whether to fill it with more or leave it as is.

THanks

Brian

 

TTT

 

No NO No!!!
All rear ends that I've dealt with have a seperate plug on the right side of the diff. You pull that plug and fill it to that level. You can fill it thru any hole but only fill it up to the bottom of the check hole. If you put too much oil in there you'll blow every seal and leak oil everywhere.

 

thanks for the reply.

Thats all I needed to know.

Brian