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Ford 9 spitting oil out vent

trying to figure out a solution to my breather vent spitting oil out. It's only when the rear end gets hot. I recently swapped a v8 in my truck so I'm guessing the added power is causing problems. Never did this before with my turbo 4. Before this last trip I raised the vent up higher but it still puked. Any ideas would be appreciated. Also I run 85-140 gear oil. Vent is on opposite side of ring gear.
I havnt filled it in a while. I think I put one gallon in or I fill to the stock fill plug level then add an extra quart because I have floater hubs. I'll try new oil and first I guess. Cleaning gear oil bath every trip out getting old haha


Well-Known Member
the stock fill plug was with the pinion angle stock is close to level. if the pinion is pointed up that could be a good bit more fluid.


Well-Known Member
With floaters I fill em, jack up one side for awhile and than the other, let it sit for awhile and stop topping of just below the fill.


Well-Known Member
You could have a bearing heating up causing the oil to boil....

Kyle D

Well-Known Member
Have you actually checked the temp? The oil may be a little too light leading to excessive temp. I've had 85/140 gear oil poor out of a bottle looking like 30w hydraulic oil before so I think there's a lot of inconsistencies with oil rating between brands. I would check your temp while you're out and then try to decide if a different grade or brand of oil is needed.

Dirtracer 619

Well-Known Member
If that red thing on the fire wall is the end of the vent line. Its not high enough when you bottom out its almost level. Try running it up higher and then out the back. Higher will let it drain back down and out the back will keep things clean

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Well-Known Member
Looks like you have a high spot between the fitting on the housing and where it runs up the link. That would prevent it from being able to drain back and keep the link portion of line full. Hard to get the line more vertical with lots of travel but maybe make the line bigger and get rid of high spots so the air and oil have a chance to pass without acting like a capillary tube.
We went to a bigger line and reservoir as suggested above to solve ours.