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TH350 lines

Discussion in 'The Garage' started by Muddytazz, Jul 26, 2004.

  1. Muddytazz

    Muddytazz 1 ton status

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    Anyone know off the top of their head what size the tranny lines from the tranny to the rad are? I have to replace them and my burb isn't here.
     
  2. diesel4me

    diesel4me 1 ton status Premium Member

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    Re: TH350

    Most of the chevy's have 5/16 metal tranny cooler lines--I've seen some with 3/8 too,but mostly on TH400's-and pretty rare..Newer ones (87and up)might be metric--I'm not familiar with the newer stuff.They get pretty bizzare on some,with those "snap lock" fittings--glad I have old junk! /forums/images/graemlins/crazy.gif
     
  3. Muddytazz

    Muddytazz 1 ton status

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    Re: TH350

    Would it hurt anything to upgrade from the 5/16" line to a 3/8" line?
     
  4. TrcksR4ME

    TrcksR4ME 1/2 ton status

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    Re: TH350

    The only side effect I could think of by upgrading to 3/8 lines would be reduced pressure, dunno if that will hurt anything though /forums/images/graemlins/dunno.gif
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    Re: TH350

    It might hurt your wallet a little--you'd need to replace the fittings in the tranny with 3/8 inverted flare to 1/4 inch pipe fittings(careful not to crack the case,use no teflon tape)and the same at the radiator(you will have to see what your radiator has for fittings,they may be pipe thread with adaptors for 5/16 tube,or inverted 5/16 fittings made as part of the radiator.Also 3/8 tube is more money(not much though)and harder to bend(the thicker wall thickness wont hurt thgough)but I dont think its really that much of an upgrade,or GM would have used it on more trucks factory--the last time I saw the 3/8 lines was on a 65 pontiac grand prix I fixed for a friend--had to send him back to the parts store with 3/8 fuel line on his rusted tranny line,so he could get the 3/8 tubing!.It might allow more flow,and would probably not rust out as fast cause they are thicker-Its up to you if you think all this will be worth it.I hate tranny cooler lines ,they rust away in less than a year around here--same with brake lines,I try not to do any panic stops in my vehicles--seems like every time I do a brake line pops. /forums/images/graemlins/angryfire.gif
     
  6. Muddytazz

    Muddytazz 1 ton status

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    Re: TH350

    Ok, i'm just going to replace the lines with the stock 5/16" lines. Anyone know how long of lines to get to be able to bend it up myself?
     
  7. diesel4me

    diesel4me 1 ton status Premium Member

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    Re: TH350

    60 inches was the longest one I can get with the ready made flares on them--you can buy couplers to screw 2 lines together,or cut and flare it yourself(kind of a PITA).Some folks use compression fittings,but they arent really intended for steel tubing,and they crimp the line some,restricting the flow. /forums/images/graemlins/crazy.gif
     
  8. dontoe

    dontoe 3/4 ton status GMOTM Winner

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    Re: TH350

    Any one ever use copper? Less corosion I would think and softer to bend.
     
  9. diesel4me

    diesel4me 1 ton status Premium Member

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    Re: TH350

    I have asked the same question here before--no answer.I've been tempted to use copper too,but I have read in GM repair manuals that aluminum and copper lines are not reccomended because they claim they will crack after vibrating awhile.I think thats bull--I might do it anyway,its better than rusty ones popping at an inconvenient time.I used 3/8 copper for the fuel lines in my plow truck(the king of corrosion!)and it turned green,but its been five years at least,and no failures.They sell copper tubing for air brakes that is heavier wall thickness,if its good enough to dtop a semi,it should hold up as a tranny cooler line,in my opinion--guess the only way to know for sure is to try it!. /forums/images/graemlins/blush.gif
     
  10. chevyfumes

    chevyfumes Court jester

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    Re: TH350

    I bent new lines for mine and I gotta tell ya , what a PITA, almost worth it to try the pre bent lines from LMC or some place, I think thier about twice as much or how bout a braided flex line???? /forums/images/graemlins/dunno.gif
     
  11. pvfjr

    pvfjr 1/2 ton status

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    Re: TH350

    Did you use one of those "benders", or a spring? I tried both and found it to be really easy with the spring style benders.
     
  12. chevyfumes

    chevyfumes Court jester

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    Re: TH350

    I used a real funky elcheapo, tell me more about the spring version or a link maybe.... /forums/images/graemlins/deal.gif /forums/images/graemlins/waytogo.gifNevermind I found it...who'd a thunk thats so simple..... /forums/images/graemlins/thumb.gif spring tube bender...
     

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