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need some advise leaky th350

Discussion in 'The Garage' started by generalleeloaded, Jul 18, 2004.

  1. generalleeloaded

    generalleeloaded Registered Member

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    hey guys, rookie mechanic here, got a bad leak in the front right of my trannie (th350). If my truck sits for a day the leak isn't to bad, but when 2-3 days pass there is a huge puddle.
    Have been doing a little research and I am going to replace the filler seal, and lines.

    My question is, is there somethings i should be looking out for? and are there any other seals that i might be over looking that should be replaced? I plan on keeping the truck for a while.

    The pan gasket is new and sealed properly.
    and I am going to have a couple extra o-rings on hand incase i booger one up, as well as checking to ensure there is no burr to cut the new seal up.
    Thanx
    any advise is appreciated!!
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    have you located the leak? it might be the seal on the pump. you have to pull the trans to replace that one though. if it is that seal, the check the bushing that is behind that seal, it may be the reason the seal went out. /forums/images/graemlins/waytogo.gif
     
  3. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Make sure the case isn't cracked. That is the most common spot for a cracked tranny case. They like to crack just above the cooler lines for some reason. I had a tranny cracked there before but it was just above where there was any fluid so mine didn't leak but any closer to the lines and it surely would have. /forums/images/graemlins/thumb.gif
     
  4. generalleeloaded

    generalleeloaded Registered Member

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    no haven't got an exact location of the leak yet.
    So I think I'll go for the seal replacement first and see what happens.
    But,
    The leak has been progresively been getting worse.
    do you think that it could be a sign of a leak from the pump seal?
     
  5. generalleeloaded

    generalleeloaded Registered Member

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    Will do crack check but I haven't been off-road with this truck yet so...
    I heard about a powertrain dye from CAT that could be added to the trannie and used in conjuction with a black light to pinpoint the leak.
     
  6. 70~K5

    70~K5 1/2 ton status

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    I'm going thru this right now. Mine is leaking at the dipstick seal. Changed the Oring and it still leaking there. I have the tranny cover part of the floorboard off and can watch it start leaking.
    I'm looking for a newer style dipstick tube that uses the one piece boot/ seal I think that will solve the problem.

    Get a couple of cans of "brakeclean" and spray the trans down and wipe it clean then start watching to see where it coming from. If you can't pull the trans tunnel "hump" then get a inspection mirror to see it from below.
     
  7. ugly_blazer

    ugly_blazer 1/2 ton status

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    Another thing in that area that can leak also is the kick-down cable.
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    I'll second the detent cable and dipstick tube--my 74 still leaks at both those places despite repeated attemps to seal them with new o-rings--I plastered some rtv on top of them after the last attempt,it only leaks slightly when I park it downhill now.I dont like using RTV on trannys,always afraid some will get inside and plug up something.
     
  9. generalleeloaded

    generalleeloaded Registered Member

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    Well did the inspection and no one was right, not that the help isn't greatly appreciated! and this one hasn't come up in any search i've done anywhere!!
    The trannie cooling line got a hole worn through it by the crossmember.
    I guess it couldn't take thirty or so yr's of rubbing contact! /forums/images/graemlins/grin.gif

    Thanks for all the input guys!!
     
  10. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    at least you found it. /forums/images/graemlins/waytogo.gif

    just don't fix it like the moron i bought my truck off did. /forums/images/graemlins/angryfire.gif he put a rubber line in the metal to help with the engine movement, it leaks about 1 quart every 3000 miles and have to tighten it up everyother week.

    use a hard line all the way. /forums/images/graemlins/waytogo.gif
     
  11. diesel4me

    diesel4me 1 ton status Premium Member

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    Must be the same moron who owned my 82 K20--I've had it since last august,on the road since december,and it still has a small peice of 5/16 fuel line on one of the tranny cooler lines,where the front driveshaft rubbed through it--and there is 3 compression fittings on it too--I've been meaning to fix it,but I got sidetracked patching rusted doors and cab corners,draining leaky fuel tank on drivers side,switching to the passenger side tank that doesnt leak(yet) and hooking up the sending unit so fuel gauge will work--I hate messing with tranny and brake lines,seems like its all you do in new england is change them on a yearly basis.I've posted about wanting to use copper lines,but I am a little leery of them work hardening and cracking,especially with all the vibration from the diesel--guess I'm stuck using the ready made"made in mexico"crap lines the parts stores sell--sigh-- /forums/images/graemlins/mad.gif
     

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