Anyone Heard Of Pressure Valves On Front Differential?

tbclrk · April 18, 2009

So my 01 Sierra was leaking fluid from the front axle seals. We replaced them and everything was fine. Then later i got a squeaking sound coming when i hit the gas, and there was a leak coming from right behind the transfer case, we couldnt figure out what it was so we took it into the dealer for a diagnostic. They said that it was a U-Joint that was bad and that the axle seals were leaking again.

So we talked to a different guy who said that there is a pressure valve on the differential and (i dont remember where he said for the other seal) but he said this could get clogged (especially if you go mudding) and when those are blocked it will just throw the fluid out the seals.

If anyone can understand this, have you ever heard of this problem?

Z45 · April 18, 2009

There is a vent hose running from the top of the axle up onto the frame. Its a breather with a little plastic valve. Sometimes they will get dirty with mud, grease etc and not let the axle vent and could cause leaks.

Its nothing expensive, crawl under and look for the vent hose, follow it up to the end on the frame and make sure the little tit sticking out moves and is free of crud. Sometimes these get ripped off off-roading or by owners who have no idea what they are there for.

tbclrk · April 19, 2009

There is a vent hose running from the top of the axle up onto the frame. Its a breather with a little plastic valve. Sometimes they will get dirty with mud, grease etc and not let the axle vent and could cause leaks.

Its nothing expensive, crawl under and look for the vent hose, follow it up to the end on the frame and make sure the little tit sticking out moves and is free of crud. Sometimes these get ripped off off-roading or by owners who have no idea what they are there for.

Alright, ill look. thanks

and why would anybody rip anything off a vehicle if they dont know what its for? that just seems stupid, but i dont doubt that it happens alot.

98 Z71 SLT · April 19, 2009

No such thing as a pressure valve in a front axle

I've rebuilt almost a dozen front diffs...no valves in there at all

There is a vent tube...that's it

They're taking you for a ride ..............

tbclrk · April 20, 2009

No such thing as a pressure valve in a front axle

I've rebuilt almost a dozen front diffs...no valves in there at all

There is a vent tube...that's it

They're taking you for a ride ..............

Ok, well i looked and what i found it looks like your right, i found a tube that goes up to inside the front fender, pulled the cap off and full of gunk. cleaned it out and hopefully it stops the leak.

Thanks!

now i get to fix a u - joint thats squeaking! (nothing to do with front diff though)