Differential Fluid Overflow out of Vent Tube
 

This is very strange because about 5 months ago I replaced the diff cover with Mag-Hytec. Everything appeared to be fine for 5 months then today it happened, fluid over flow through the vent tube.

The only thing I can think of is the ambient temp is now colder 45F. What do you think?

BTW, I used Purple Synchromesh gear oil.

This strange phenomenon really has me scratching my head.

On a Mag-Hytec does the fill hole set the proper level, or do you have to meter it in correctly yourself. Nothing to me explains why this would happen after 5 months. Colder temps wouldn't make your fluid expand. All I can suggest is double check your fluid level and make sure your vent line is totally clear.

Was the truck level when you filled the diff?

Thank you for your reply guys.
Anyway, I'm not alone on this issue, found a few others have had the same experience, it's a screwed up by Mag Hytec and their MIN MAX marks. If you go by their MIN MAX marks you will be over filled.

Here is a thread I found from other people.

So I removed a little over one quart of fluid and using the Mag Hytec dipstick it measured about an inch from the bottom of the dipstick.

But, cold temperature somehow expand synthetic oil more than Summer and thus it overflown where as it didn't during warmer weather.