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Tranny keeps overheating!!! HEEEEELLLLPPP!!!

Discussion in 'The Garage' started by zakk, Mar 2, 2003.

  1. zakk

    zakk 1/2 ton status

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    I was on the freeway back from Hollister Hills and my tranny hit 215* doing 70!

    i rinsed it out, so there was no mud in it, and it got back to 190* and I limped it home.

    What can be causing this?

    Rig Specs:
    GMPP SBC 350 with Edlebrock intake, HEI, headers, Q-jet (~290 hp at the flywheel)
    TH350 with ~1500 miles on it tops! (motor also only has ~1500mi. on it)
    24,000# B&M Stacked Trans. Cooler
    TCI deep Pan (2 extra quarts of capacity)
    AutoMeter Pro-Comp 2 5/8 electric trans. temp guage (plumbed into the pan)
    NP203 w/ Part Time kit
    Dana 60/ 14 bolt full floater w/ Detroit
    4.10 gears
    39.5x15x16.5 TSL's on Steel Wheels (make unkown)

    I am at a total and utter loss. Please help.

    Thanks in advance

    *edit* more complete rig info listed
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I'm no tranny guru but that temp sounds within operating range to me...

    How big a cooler do you run?

    Rene
     
  3. zakk

    zakk 1/2 ton status

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    24,000#...biggest one they make! and the stacked fin is a superior design to the tube sytle...but it doesn't seem to help me a bit! /forums/images/graemlins/confused.gif /forums/images/graemlins/frown.gif
     
  4. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Is the tranny slipping at all?

    I think as long as the temp stays near the engine temp it should be fine...

    Rene
     
  5. zakk

    zakk 1/2 ton status

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    it is shifting funny. I am not sure how to feel if it is "slipping" at highway speeds, but it doesn't feel normal. shifts are weird, no power to pass, difficulty downshifting into passing gear.
     
  6. Hossbaby50

    Hossbaby50 3/4 ton status

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    Where is the temp reading coming from? Pan, return line, diagnostic port? I usually run about 160 on my return line which I am guessing is around 190 on the actual temp. I don't start to sweat it until my temp on the return goes above 200* on the return line.

    I have been told that standard operating temp for tranny fluid is 150-250*, so 190-210 doesn't seem to out of line. But this is all what I have been told, and I don't know them to be fact.
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I assume you checked the obvious like fluid level, leaks, etc etc? If so maybe the modulator is having issues? IIRC the TH350 uses a vac modulator for shifting and a cable for downshifting right? If either of those are not working right it will cause more heat as it lugs or shifts incorrectly. The 4.10's and 39.5's aren't helping any either, but I'm sure you already know that.

    Rene
     
  8. zakk

    zakk 1/2 ton status

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    Yes, the 4.10's are not helpping in the slightest.

    The sender is in the pan. no "bad" leaks. a little bit of wetness occasionally, I also have a Deep TCI aluminum pan (extra 2 quart capacity)

    I am really thinking that the 4.10's are behind this. it is the only thing i can pinpoint as a problem. Maybe someone else can shed some light on this problem, as I am not seeing it...
     
  9. Hossbaby50

    Hossbaby50 3/4 ton status

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    How many RPM are you turning on the highway? Do you have a tach to know? If the th350 has a lockup converter and you don't get to the stall speed and lockup point your tranny will get hot because the torque converter will slip and cause heat. I don't know much about the th350, but they say it is like a 700R without OD. If it is like my 700 I have to keep it above 1600-1800 RPM to keep the TC locked and from slipping.

    Now that I run 4.56 gears and 32's this isn't a problem anymore, but before with the 3.73 in OD it was from time to time.
     
  10. Sandman

    Sandman 3/4 ton status Author

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    Its the 4:10's and the 40"s. I ran that exact combo for about a year and the tranny ran warm. It ran cooler when I took the radiator out of the loop. Seems the hot radiator was helping to keep the tranny fluid warmer. bypassing it made a big difference.
     
  11. zakk

    zakk 1/2 ton status

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    i am turining 2500 or more to keep up with traffic. my stall is 1600 rpms.

    Sandman--

    i think I will give that a go this week on my day off. the reasoning is sound, i was advised to keep the radiator line, but at this point, i'll try anything.
     
  12. ducttape114

    ducttape114 1/2 ton status

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    do you have access to a set of 33s or 35s? if you could borrow some you could see what happens when you have a little better gear rato/ tire size set up. that would help you figure out if thats your problam.
     
  13. Z3PR

    Z3PR Banned

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    I'd be willing to bet it's the 4:10/39.5 combo. Might wanta try a dual inline filters. Alittle more filtering and extra fluid capasity is never a bad thing in my opinion. Something like [​IMG] only with 2 filters.
     
  14. Sandman

    Sandman 3/4 ton status Author

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    [ QUOTE ]
    i was advised to keep the radiator line, but at this point, i'll try anything.

    [/ QUOTE ]

    So was I. By people who had never done it. That seems to happen a lot. I live in what can be a very cold climate and I have never had a problem with the fluid being to cold. Maybe it would be more of an issue further north though.

    I didnt know you ran a stall. I also ran a 2400 stall and it will heat up on you even with the extra cooling. I ended up mounting a cheapo electric fan in front of the B&M cooler that I can switch on. I only need it when I'm in the rocks or deep mud.
     
  15. zakk

    zakk 1/2 ton status

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    that is the concerning part, mine does it at speed when the air passing through the radiator should be at its highest point...
     
  16. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Zakk,

    You know it might be unrelated, but did you notice your truck running "rough" around the time we pulled off the highway? I dipped into the throttle a couple of times and the engine hesitated and stalled....I was left wondering if "Jesse's Gas" was the culprit?!

    I know Ryan says he's pretty familiar with the symptoms of "bad gas"....all my temps were fine, but that stumbling was NOT something I'd experienced before. Maybe the gas was not burning well and causing high temps as a residual effect?????

    Just a WAG, but I thought I'd share that info since I had some "weirdness" too.
     
  17. zakk

    zakk 1/2 ton status

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    true...motor did feel a bit funny, but the trans is a problem I have had for a while. I'll try throwing some 92 octane and maybe a booster in there to see if it was bad gas. I really need to get the FI on, as I bet the Q-jet isn't feeding my mouse the way it should...
     
  18. Triaged

    Triaged 1/2 ton status

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    190* isn't hot.
    210* isn't really hot either but getting a bit warm.
    If it was above 220* I would worry about it.
     

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