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Differential vent tube overflowing?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 88K5Jimmy, Apr 4, 2004.

  1. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    I filled the dif on my 14bsf and now the vent tube is flinging dif fluid out of the top of the vent line. I noticed this because there was fluid on the top of my gas tank (where the vent tube ends) and numerous specs of fluid on the back of my tailgate and rear window.

    What do you think is causing this?

    Thanks
     
  2. Blue85

    Blue85 Troll Premium Member

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    If your axle is spitting out a lot of oil, it is either overheating or overfilled.

    I have a 14sf, too and it occasionally spits out a little oil. I see it on the diff cover, but when I check the oil level, it is never noticeably low.

    If yours is ending up on the back window, it must be putting out a lot more than that.
     
  3. Can Can

    Can Can Pusher Man Staff Member Super Moderator

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    Make sure that the vent tube end isn't plugged up. When they get plugged, they will cause the diff to hold too much pressure. When enough pressure builds up in the case, the valve is forced to pop and a decent amount of fluid can spit out. Chances are, though, that if it was plugged up it's not anymore!!!! /forums/images/graemlins/wink.gif
     
  4. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    Still happening. It seems like the dif is pressuring up. I thought about plugging the other end of the vent tube ( the part that goes up on top of the gas tank) and putting a hose clamp on it. However, I don't want to blow out a seal in doing that. Anybody have any clues?
     
  5. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    Did you check the fluid level? Have you been in any water lately? I have seen it where sometimes water gets in but lube never leaks out. Don't ask me how that is possible cause I can't tell you. Anyway you end up with a bunch of water in there and it works the same as being way over full.
     
  6. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    I hadn't been in any water before this weekend. The dif was low last time I checked it but since then it had stopped but then started blowing more fluid out. It seems that from 65-75 mph it will build up the pressure and then leak out from the vent tube.
     
  7. 84_Chevy_K10

    84_Chevy_K10 Banned

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    I'd take some compressed air and blow out the line and fitting in the diff.
     
  8. DPI

    DPI 1/2 ton status

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    I had the same problem with 14FF after installing the ORD shackle flip. I am running 9" of lift in the back and a CV'ed shaft. So the pinion is pointing up at the shaft using 6* shims + the extra angle from the ORD flip. On mine, I beleived the problem to be too much angle on the pinion and thus gear oil being pushed out from the ring gear spinning during normal driving.

    I wanted to make sure the front pinion bearing was getting plenty of lube so I made sure I filled the axle as much as I could - within reason.


    I did a couple things to help the symptoms.

    I installed a Fram in-line fuel filter (this helps keep any dust out for the rear-end) in the vent tube and I extended the tube up to my fuel filler inlet.


    No more overflowing...
     
  9. nofeartruckin00

    nofeartruckin00 1/2 ton status

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    Your pinion seal could be leaking, throwing the gear lube side to side. Have you checked that possibility also? Or if you have alot of specs of fluid in one particular wheel well, your wheel seal could be shot. Just thinking out loud.
     
  10. 88K5Jimmy

    88K5Jimmy 1/2 ton status

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    I think I figured out what the problem was. The housing is rotated up due to the shackle flip, therefore causing the fliud level to read low. I think more fluid was added thinking it was low a while ago, thus causing it to pressure up and expell fluid from inside the dif. I replaced the fluid and put a inline filter on the vent tube. So far so good, just have to get it on the highway to find out since that is when it seemed like it overflowed the most. However a busted heater core is keeping me from doing that /forums/images/graemlins/dunno.gif
     

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