Changing Differential Fluid

[truekoa]

Hi Guys,

First time doing this on my 84 C10. What and how much fluid do I need? How do I know when to stop, should the liquid just squirt out when its full from the filling hole?

Anything else I need to know about when doing this?

Thanks!

 

[PrairieDrifter]

Yup you just fill it up until the gear oil starts dripping from the fill hole.

Its 80-90w, I'm not sure how much exactly but just get a few quarts of it.

Are you just replacing the fluid or adding to it? The only other thing is to check if your axle seals are still good then, if you don't have the diff cover off already you can take it off and clean the diff housing out and do a look over of the diff then you can make a new gasket for the cover so it doesn't leak.

 

[smoothandlow84]

And just another quick tip. When flushing iut the rear or front diff oil, with the cover removed, wear rubber or better yet nitrile gloves . Reach into the bottom part of the diff and gently scrape the oil towards the cover side. You'll be shocked how much dark slimy crud builds up and settles in there. I use the red high temp siliconized gasket maker as well as installing a new gasket. I also wait a few hours before filling up the diffs with fresh oil. Nothings worse then a leaky diff cover after new oil is installed. A 3/8" drive socket wrench works well to remove the filler plug at the top of the differential.