I noticed when I got my car ('71 Vista, open type rear) fluid dripping from the axle vent and the underbody and the tailpipe had a film of oil aft of the vent. I checked the differential (when it was cold) and the fluid was just even with the bottom of the filler hole. I was a grease monkey for a few years and that was the way to check them that I learned, maybe I'm wrong?
I took the car out the other day and after about a half hour I detected the distinct smell of gear grease so I got right back home. I checked under the car and fluid was dripping out of the vent and was cooking on the tailpipe (the smell) also blew back on the underbody. I got a drain pan and took the drain plug off the rear and maybe a quart of fluid came out?
I checked them hot and cold at the gas station and never had this happen, but I won't assume it never does.
Is there a way to overfill them? or do I have another problem? All I could figure was fluid expansion (that is a lot) fom the heat or the rear has to be filled and checked differently than the norm and was overfilled, or? The manual just says how much and what type gear fluid.
I waited for the oil to stop dripping then capped it back up and tested it and the car seems to be fine, no dripping or blowing out, got me.


Allan

 

8.5" differential capacity is approx. 4.25 pints.

you were checking it right. level s/b even with the bottom of the plug hole when the rear end is cold and level(side to side).

i don't know what to say about you being able to drain about a quart out when hot, but the level being right when cold. the fluid doesn't expand that much. only thing i can figure is the fluid is bad and foaming up when driving.


bill

 

Thanks for the reply.
I never thought of foaming but it makes sense, that is a lot of fluid. I'm going to pull the cover and drain it then put in the correct amount and type gear oil and go from there.

Allan