Originally Posted By: JTK
Chris, are you sure the OEM was a check valve? Reason I ask is; They should be able to breathe in/out in response to heating/cooling, or you're gonna have leaks and ruptured seals.
I think the main thing is to make sure your vent hose is well secured, up as high as you can get it and it's not clogged with mud. I've seen them clumped with mud on the open end.
I do recall having a breather element looking plastic tip on the vent hoses of both my Jeep's rear diffs (1994 Cherokee, 1997 Wrangler). Don't recall what was on the fronts.
Joel
I'm sure Chris had a check valve. I have never seen a Jeep with any type of filter on an axle housing. The M38 / M38A1s had venting systems for deep fording though. As I stated in my previous post, the typical heating and cooling cycle of the diff does not cause enough differential pressure to close the check valve. When you submerse a hot diff in cold water, that's when the valve closes. The closing under this condition does not rupture seals or cause leaks.
Originally Posted By: JTK
I do recall having a breather element looking plastic tip on the vent hoses of both my Jeep's rear diffs (1994 Cherokee, 1997 Wrangler). Don't recall what was on the fronts.
Joel
The breather element looking plastic tip was a simple check valve(they are often white in color). The Dana 30's in both your XJ's also had one.