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Thread: Torque converter clutch fails to engage when tranny is hot

  1. #1
    Registered AviatorJud's Avatar
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    Icon928 Torque converter clutch fails to engage when tranny is hot

    On hot days or when I'm hauling a lot of weight, or both, and the transmission fluid gets up around 220 or so, the TCC stops working and won't work again until I stop, shut it off and let it cool down a bit. Has been happening off and on for several years now. If you know anything about torque converters, you know that whenever the TCC isn't locked, the slippage in the converter is generating a good deal of heat, so whenever the clutch goes out, it starts heating up even more, especially when on the highway.

    Got over 200K on this Jeep, and over the years I've done preventative maintenance to keep the tranny alive longer...ie, adjusting the TV cable for later, firmer shifts...slightly increasing the valve body hydraulic pressure screw for stronger clutch engagement..adding lucas transmission additive to increase the fluid viscosity, also increasing clutch pressure...and using full synth ATF. Shift quality is great, still very firm with no slippage. The converter clutch is the only thing I've had issues with.

    So anyone know why the clutch wont engage when the fluid gets hot and how to remedy the situation?
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

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    Senior ********* Taz's Avatar
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    probably because it's wore out at 200,000 miles?? Maybe the lock up circuit failed?


    FYI I got 224,000 miles out of my old 46RH in the old V8 ZJ I had, no TCC issues, but I was running a BIG tranny cooler on it too. Like a 24,000# GVW cooler meant for a motor home.
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    Registered AviatorJud's Avatar
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    Quote Originally Posted by Taz View Post
    probably because it's wore out at 200,000 miles?? Maybe the lock up circuit failed?


    FYI I got 224,000 miles out of my old 46RH in the old V8 ZJ I had, no TCC issues, but I was running a BIG tranny cooler on it too. Like a 24,000# GVW cooler meant for a motor home.
    It's not worn out and the circuit obviously didn't just fail...it works flawlessly EXCEPT in these circumstances where the fluid gets really heated up. Doesn't happen very often but almost always when I'm hauling a lot of weight on the highway and I need it to work properly. Mine is a 44RE with 207K on it currently. Thinkin maybe just replacing the TC. They're only $150 or so.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

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    wine taster kjk's Avatar
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    If you still have that check valve in the tranny line get it out of there. It could be partly clogged and restricting the flow.
    5.9 ZJ SCT tuned PCM/ KJK CAI/ Thorley headers with 3" Magnaflow cat and muffler/ Modded kegger/ TransGo shift kit/ Vanco brake kit/ Braided steel brake lines/ Mopar cupholder insert!

  5. #5
    Registered AviatorJud's Avatar
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    Quote Originally Posted by kjk View Post
    If you still have that check valve in the tranny line get it out of there. It could be partly clogged and restricting the flow.
    First, what check valve?

    Second, why would it ONLY restrict flow once the fluid reaches a certain temp? If anything, hotter fluid would flow past a restriction better because it would be less viscous.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

  6. #6
    wine taster kjk's Avatar
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    Quote Originally Posted by AviatorJud View Post
    First, what check valve?

    Second, why would it ONLY restrict flow once the fluid reaches a certain temp? If anything, hotter fluid would flow past a restriction better because it would be less viscous.
    The check valve is in the transmission line that runs to the radiator. It's at the end of the metal line where it transitions to rubber hose.
    If this is partially restricted it can cause transmission overheating. Once the trans gets to a certain temp. the PCU keeps the trans from going into overdrive and locking up.
    I'm not saying this is the problem, but removing this valve is recommended by most custom transmission builders. I removed mine years ago with no ill effects.
    5.9 ZJ SCT tuned PCM/ KJK CAI/ Thorley headers with 3" Magnaflow cat and muffler/ Modded kegger/ TransGo shift kit/ Vanco brake kit/ Braided steel brake lines/ Mopar cupholder insert!

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    Well I am not getting into a discussion fluid for these trannys. Its been beat to death. However, it does not appear that you have a tranny cooler added (in front of the rad). Its a must if you're towing regularly. Even more important than fluid changes since it keep the fluids at their normal range. Over heating affect the fluild and both affect the transmission.

    The rad may be tired and not cooling the fluid from the immersion cooler sufficiently as well. Many factors... also when towing a heavier load, climbing grades, accelerating with the load you want OD off nearly always. You can get away with it a bit more in the winter but certainly not in hot weather or regular temp in the summer.
    Last edited by tripplec; 05-09-2011 at 09:38 AM.

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  8. #8
    Registered AviatorJud's Avatar
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    Quote Originally Posted by tripplec View Post
    Well I am not getting into a discussion fluid for these trannys. Its been beat to death. However, it does not appear that you have a tranny cooler added (in front of the rad). Its a must if you're towing regularly. Even more important than fluid changes since it keep the fluids at their normal range. Over heating affect the fluild and both affect the transmission.

    The rad may be tired and not cooling the fluid from the immersion cooler sufficiently as well. Many factors... also when towing a heavier load, climbing grades, accelerating with the load you want OD off nearly always. You can get away with it a bit more in the winter but certainly not in hot weather or regular temp in the summer.
    I have the tow group, so I do have the secondary oil cooler in front of the ac condenser. Whenever I'm actually towing a trailer, I always keep OD off. As I said, the transmission works perfectly EXCEPT for the TCC failing to engage at higher temps. If there was really a problem with the fluid, other functions would be affected as well. Furthermore, the temp where the problem occurs(~220F) is not even the overheat range, which is above 260 I believe.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

  9. #9
    Registered AviatorJud's Avatar
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    Quote Originally Posted by kjk View Post
    The check valve is in the transmission line that runs to the radiator. It's at the end of the metal line where it transitions to rubber hose.
    If this is partially restricted it can cause transmission overheating. Once the trans gets to a certain temp. the PCU keeps the trans from going into overdrive and locking up.
    I'm not saying this is the problem, but removing this valve is recommended by most custom transmission builders. I removed mine years ago with no ill effects.
    I'll look into the check valve, but I've done many flow tests before and it's always fine coming back from the aux cooler. Also, it's not as if the tranny overheats on a regular basis. It's always when doin some hauling in hot weather(95F). Stop and go traffic especially.

    Also, when the fluid overheats, the PCU locks out OD, but it absolutely is supposed to lock the TCC, otherwise the fluid would not cool down and would actually continue to heat up, like in my case. That's why I'm saying this is not normal behavior nor and I figure out why it's doing it when all other functions work perfectly. There are no codes either.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

  10. #10
    the logical one fixer5000's Avatar
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    why not try using the fluid chrysler reccomended? this has solved many issue for folks on this board in the past. fresh filter cant hurt either. why have you let this go for a few years???
    99 grand cherokee...mine...gone... now its a 2011 toyota tacoma sport... double cab longbed 4.0 and the are cap to match... im loving it !

    98 grand cherokee...wifes
    nothing special just jeeps.....

    "GET THERE FAST BUT ARRIVE ALIVE "

    automation is the future of manufacturing in the USA... if youre a box packer youre screwed. get educated now


    my jeeps gone. two engines were just too much to handle. now i got me a toyota lets see how long that lasts

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    Well maybe 260 is very hot but transmission cooked or cooking depending how long it stays there and the fluid is also going south fast. At least its trying to cool itself by disabling OD. Since there is not mention of the engine temperature I presume its normal and not on the hot side as well. As posted by Fixer.. and others flow may likely be the issue. Tranny filter and check valve are cheap fixes if thats it.

    I have an I6 and added my own cooler but I never say any rubber hose in the line to located the check valve for the torque converter. I have read about it but existance and something that should be looked at. I've had my fluid changed a few times and do a few liters now and then when doing oil changed by siphoning it out the fill tube and putting fresh ATF+4 back in.

    2002 Grand Cherokee Laredo WJ 4x4 283,000km Jan. 2014
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    2009 Jeep Compass 4x4 North Edition, 2.4L, CVT
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    Nokian WRG2 tires (poor wear, cup easy and real noisy now)
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  12. #12
    Registered AviatorJud's Avatar
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    When did I say I wasn't using the recommended fluid?? I am using valvoline full synthetic ATF+4, which i change, along with the filter, every 20K miles. I feel like you guys aren't reading my entire post.

    This is not a question about why the temps are high - I know why it gets high on a 95F day, with a/c on, in stop and go traffic, while hauling a load - the engine and trans temps are both a littlle past normal on those days. MY QUESTION is why on those hot days does the torque converter clutch go out suddenly and not start working again until I shut it off and let everything cool off a bit. Again, I have NO other transmission issues and have been very diligent with the preventative maintenance all these years.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

  13. #13
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    "..adding lucas transmission additive to increase the fluid viscosity, also increasing clutch pressure...and using full synth ATF. "

    Enough said on that from post #1.
    The 220 temp is deemed as hot and sensors turning off OD. Check with transmission shops of the tranny. Normal is around 170-180F and the HOT spec for the WJ is 180F.

    2002 Grand Cherokee Laredo WJ 4x4 283,000km Jan. 2014
    I6 4.0, Transmission Cooler
    Class III In-Bumper hitch
    Westin Safari Light Bar w/big amber driving lights
    Nokian WR SUV All Weather Plus 245P70R/16 - retired due to wear
    Yokohama Geolandar I/T 245P75R/16 on it now. Winter 2014

    2009 Jeep Compass 4x4 North Edition, 2.4L, CVT
    101,000km
    Many problems with the Compass - DON'T BUY CHRYSLER JUNK

    Nokian WRG2 tires (poor wear, cup easy and real noisy now)
    Markham, ON
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  14. #14
    Registered AviatorJud's Avatar
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    Quote Originally Posted by tripplec View Post
    "..adding lucas transmission additive to increase the fluid viscosity, also increasing clutch pressure...and using full synth ATF. "

    Enough said on that from post #1.
    The 220 temp is deemed as hot and sensors turning off OD. Check with transmission shops of the tranny. Normal is around 170-180F and the HOT spec for the WJ is 180F.
    Ok. Once AGAIN, you're not READING WHAT I'M SAYING.

    OD is NOT getting turned off. It is in 4th gear with the torque converter clutch DISENGAGED. Per the service manual, OD doesn't get locked out until the fluid reaches 260F, and then it down shifts to 3rd and ENGAGES the converter clutch. The whole point being that if the fluid is too hot, you WANT the converter clutch engaged, to reduce the heat generated by the unlocked torque converter. Furthermore, the temp never gets anywhere near 260F, and almost never higher than 220F, which is completely fine and will happen almost every day here during a texas summer. Another reason why it's a good idea to use synthetic trans oil. Mine is always bright red and never smells burnt. You'll find that synth fluid is always recommended in a vehicle that sees heavier duty, mainly because it holds up better at higher temps.

    So...back to the point...there is obviously some mechanical reason why the clutch stops engaging at higher temps. Again, everything else with the tranny is FINE and it shifts very firmly. It may be that the converter clutch material is worn down after 200K and the converter needs to be replaced, but I wanted to see if anyone here knows anything more than I do about it. But that doesn't appear to be the case.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

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    the logical one fixer5000's Avatar
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    so replace your converter and clutch. you seem to know what your talking about so do it. all done here
    99 grand cherokee...mine...gone... now its a 2011 toyota tacoma sport... double cab longbed 4.0 and the are cap to match... im loving it !

    98 grand cherokee...wifes
    nothing special just jeeps.....

    "GET THERE FAST BUT ARRIVE ALIVE "

    automation is the future of manufacturing in the USA... if youre a box packer youre screwed. get educated now


    my jeeps gone. two engines were just too much to handle. now i got me a toyota lets see how long that lasts

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    Registered AviatorJud's Avatar
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    Quote Originally Posted by fixer5000 View Post
    so replace your converter and clutch. you seem to know what your talking about so do it. all done here
    Thanks chief.
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

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    Can you tell me more about the check valve? I've been having tranny over heating issues lately. Is it on the pressure line? How do you remove it? I may try this, thanks a lot. Sorry not trying to
    hi-Jack your thread!
    95 ZJ limited 5.2 242 swap, 2"BB 31" TrXus. (rolled)
    98 ZJ limited 5.2 242 swap, 2"BB 31" TrXus. (current)

  18. #18
    Registered AviatorJud's Avatar
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    Quote Originally Posted by 95ZJ View Post
    Can you tell me more about the check valve? I've been having tranny over heating issues lately. Is it on the pressure line? How do you remove it? I may try this, thanks a lot. Sorry not trying to
    hi-Jack your thread!
    No worries, doesn't seem like I'm gonna find what I was looking for in this thread anyway.

    I checked the FSM and it doesn't get into specifics about the check valve location except to say that it IS in the pressure line close to the radiator. Another person mentioned it being near where the rubber hose section of the line is, again near the radiator. However just looking at the line, nothing was obvious. I also have a feeling the location may depend whether you have the factory aux oil cooler that came with the tow package or not. Maybe someone who has removed it will chime in...
    Jud

    '96 ZJ Limited 5.2L, NP242 conversion, Tow group, Chargold(what's left of the paint, that is)
    .75" coil spacers up front / 1" coil spacers and UC coils in back / 31x10.5R15 BFG AT's on AR black steelies / Stillen rotors / Bilsteins / Kevin's Front Trackbar / OME SD40 / JKS QD's / FIPK / Kolak's ignition / Kolak's 3" exhaust / 5.9 e-fan upgrade / 5.9 alternator / Optima Yellow Top / B&M tranny temp gauge / Rusty's hooks / Homemade roof tire carrier / lots of little tweaks and goodies.

  19. #19
    the logical one fixer5000's Avatar
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    Quote Originally Posted by AviatorJud View Post
    Thanks chief.
    youre more than welcome spud
    99 grand cherokee...mine...gone... now its a 2011 toyota tacoma sport... double cab longbed 4.0 and the are cap to match... im loving it !

    98 grand cherokee...wifes
    nothing special just jeeps.....

    "GET THERE FAST BUT ARRIVE ALIVE "

    automation is the future of manufacturing in the USA... if youre a box packer youre screwed. get educated now


    my jeeps gone. two engines were just too much to handle. now i got me a toyota lets see how long that lasts

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    Yeah I don't have the tow package so no external cooler. My problem is my tranny will over heat just driving slow on simple gravel trails, trails that my friend checks oil wells on and drove with his Escort! It's pretty sad that a little ford escort can drive where my tranny in my JEEP will overheat!
    95 ZJ limited 5.2 242 swap, 2"BB 31" TrXus. (rolled)
    98 ZJ limited 5.2 242 swap, 2"BB 31" TrXus. (current)

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