Thread: Gear lube blowing out vent on a 9 inch

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It done it when I first got the car but the vent tube in the housing was loose so I repaired it and after a long trip its doing it again,I thought the pinion seal went bad but the hose from the vent goes up in the frame and it was dripping down near the yoke. I checked the lube and it was almost full but what could cause the lube to heat up that much to blow out the vent unless I over filled it. Jeff

If it's still full know Jeff, sounds like it was overfilled... 9" rears are fussy on fluid level and will definitely blow out any excess..... Long trips will build up a bunch of heat, think I'd just watch the level for awhile....

What is the level of the gear oil? Usually the 8 and 9 inch Fords call for filling to within 3/8" below the plug bung threads. If it flows out when you pull the plug, it's too full.

....and yes, this information is from my ancient Ford Maintenance Manuals, a '73 as well as a '79, not from my age weakening memory .

Some 9"s seem to like the oil level down a bit, like where you can just reach it with your pinkie. CAUTION!! Don't get your finger stuck! (And don't ask how I know that!!)

How do you know that...........

I usually fill them untill the lube runs out so I will stop doing that. Jeff

Originally Posted by pro70z28

How do you know that...........

That's just one of them things when people ask you just say, "Don't ask me how I know that!"..... I use the answer quite frequently......