I have a 85 s10 blazer 4wd and I'm needing to know how many quarts of fluid the rear differential holds? I know you usually fill it up till it drips out of the fill hole. But mine was over tighten and someone welded a bolt to the plug and overtightened it again and I broke the bolt trying to get it loose, so I took the rear end inspection plate off and drilled it and welded a nut and bolt setup to it, now I can fill it up from the back cover but I'm sure it's sets higher than the original one and I don't want to overfill it. Any help is really appreciated.

 

honestly the only big issue with overfilling a differential of this type is A wasting fluid and B it will **** out the vent hose, i believe its something like 2 quarts or so if you are worried about making a mess in the driveway.


Depends on axle size, of course an 8.5 Saginaw will take more then a 7.625.

 

Measure the distance from the bottom of the original fill hole to the ground. Then, make a mark on the back of the cover at the same height. Use a zip tie or a piece of wire as a dipstick to tell when it's up to the mark you made.