I just made a coast-to-coast trip landing me in San Diego. I noticed the smell of diff fluid when I stopped. I look under the car and there is a drop of fluid under the rear diff. The last time I drove through mountains (smokey mountains last time) I noticed a slight smell also. I have not noticed it any other time. The diff has a vent on top- any chance that maybe the hills + speed is causing fluid to come out of the vent? The diff was last filled by me- all the way up. Just hoping noting too serious going on.
rear diff leaks, only in the mountains?
- Thread starter joaks
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Is this a leak or just smell?
Looks like a leak- i have a drop of fluid on the driveway.
Kestas
Staff member
Check the seals.
Originally Posted By: Kestas
Check the seals.
Arf Arf Thats seals barking. While you're checking stuff, check the levels in the pumpkin.
Check the seals.
Arf Arf Thats seals barking. While you're checking stuff, check the levels in the pumpkin.
Actually, I would suspect the vent.
Pressure goes up with heat, then outside pressure drops from altitude, which forces a bit of fluid out of the seals...
Vents are usually really easy to replace. I'd start with that.
Pressure goes up with heat, then outside pressure drops from altitude, which forces a bit of fluid out of the seals...
Vents are usually really easy to replace. I'd start with that.
It could be overfilled too. The oil level in the diff is correct when it is about 1/2" below the hole. What I do is I take my pinky finger, hook it over and stick it into the hole. If it comes out with oil on it, the level is ok.
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Yah, could be either of those things too. I came to the conclusion that I had been over filling diff and creating leaks from increased pressure and heat. Diffs get warm lube gets thin. I saw an antique BMW with a belt driven fan to cool the diff. never considered it to be an issue, but I'm a flat lander.
Originally Posted By: andyd
I saw an antique BMW with a belt driven fan to cool the diff. never considered it to be an issue, but I'm a flat lander.
All my ride-on mowers have a fan to cool the hydrostatic transmission and differential unit. Maybe they are in the same design and performance envelope as the BMW?
I saw an antique BMW with a belt driven fan to cool the diff. never considered it to be an issue, but I'm a flat lander.
All my ride-on mowers have a fan to cool the hydrostatic transmission and differential unit. Maybe they are in the same design and performance envelope as the BMW?
differentials get hot, especially in mountains. I know racers that have a pump that circulates diff oil through an oil cooler.
Also if it is slightly overfull, it will burp out of the vent when it gets a little hotter than normal.
We had an F350 that cooked the paint of the diff cover the first time we pulled a 4 race car trailer (with tools and 4 people) through the mountains.
Also if it is slightly overfull, it will burp out of the vent when it gets a little hotter than normal.
We had an F350 that cooked the paint of the diff cover the first time we pulled a 4 race car trailer (with tools and 4 people) through the mountains.
Hopefully it was just a burp.
I really want to check it- I have the tools to do it, fresh Amsoil diff fluid and a handy pump BUT none of them are here. Just moved and I won't get the rest of my tools till Monday. The OCD is eating me up...
Driving the wife's car until I can check/fill. It seems that if it was a full leak it would have been empty long before my 2,500 mile trip ended.
I really want to check it- I have the tools to do it, fresh Amsoil diff fluid and a handy pump BUT none of them are here. Just moved and I won't get the rest of my tools till Monday. The OCD is eating me up...
Driving the wife's car until I can check/fill. It seems that if it was a full leak it would have been empty long before my 2,500 mile trip ended.
If the actual angles of the inclines were great enough, combined with the added heat/strain of the climbs and even a slight over fill, it could easily be 'puking' out of the vent.
Originally Posted By: Astro14
Actually, I would suspect the vent.
Pressure goes up with heat, then outside pressure drops from altitude, which forces a bit of fluid out of the seals...
Vents are usually really easy to replace. I'd start with that.
This was my first thought too.
Actually, I would suspect the vent.
Pressure goes up with heat, then outside pressure drops from altitude, which forces a bit of fluid out of the seals...
Vents are usually really easy to replace. I'd start with that.
This was my first thought too.
I've seen people replace an axle seal 2-3x and still have it leak just to find out that it was a plugged vent tube.
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