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differential vents

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by snidgen, Mar 28, 2000.

  1. snidgen

    snidgen Registered Member

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    how important are the vents on the top of my differentials. one of my buddies have his pluged but one says keep the factory vent tube. whats the deal man?
     
  2. Eagle86K5

    Eagle86K5 1/2 ton status

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    Heat can cause pressure differences in the differentials, that is why the vent is there. If you plug them off , where is the pressure to go?...thats right...it will leak out around the seals...and what else there might it also push out of the seals?...thats right the lubricant. Leave the factory vents as they were. There are a few things the engineers did do right on the Blazers.....[​IMG]

    <font color=green>Eagle86K5[​IMG]

    <font color=red>Only guy I know that can get out of line in a one car funeral
     
  3. jarheadk5

    jarheadk5 1/2 ton status

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    Or the opposite can happen. You cross a stream or watery mudpit, and your nice warm/hot rearend goes swimming in the cold water. Well, suddenly it cools off and wants to suck some air in. If the vents are plugged, in comes the water and/or mud thru the axle seals or pinion seal to cause hatred and discontent amongst the gears, bearings, and oil.

    This is bad.

    Leave the vents alone. If the hoses are broken or dryrotted, replace them. If you regularly take your truck swimming (water crossings), extend the hoses up to the top of the firewall and cap them with the cheapest fuel filter that you can find with the right-size fittings. I have a friend that ruined a 1-month-old set of rearend gears and bearings in the above scenario.

    [​IMG] Semper Maintenance!
    [​IMG] So many ideas, so little money...
     
  4. DangerB

    DangerB 1/2 ton status

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    The front vent is up near the hood, but the rear and t-case vents are right under thefloor. I know that I get that deep alot. Raise em up if you go that deep and leave them vented for reasons above.

    DangerBrett[​IMG]
    <font color=blue>harder, faster, longer, stronger</font color=blue>
     
  5. Crash90K5

    Crash90K5 Registered Member

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    Re: differential vents - Are their others?

    You have one for each diff, I can find those easy... T-Case (NP241)? Tranny (T700)? Which side/front-back are these on?

    [​IMG] <font color=blue>Crash90K5</font color=blue> [​IMG]
     
  6. DangerB

    DangerB 1/2 ton status

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    Re: differential vents - Are their others?

    Here is where its at on my '74/'79.Look above the rear tailshaft output on the t-case. Its only a couple inches long with a little vent thing on top. If its not there feel for a nipple it would go on. If thats not there ask someone with newer truck. Im gonna go up through the floor with the 2 rear vents.

    DangerBrett[​IMG]
    <font color=blue>harder, faster, longer, stronger</font color=blue>
     

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