Engine occasionally shudders at 45-60 MPH, but only when towing?

Discussion in 'Etrailer.com Trailers and Towing Forum' started by HotelRoyale, Oct 11, 2017.

  1. generok

    generok Well-Known Member

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    Feb 7, 2013
    Anchorage, AK
    If you want to check and see if it is your torque converter lock up, there's an easy test.

    When you get it up to speed and it begins shuddering, without letting off on the gas, use your left foot to LIGHTLY step on the brake JUST enough to get the brake lights to come on. As soon as that happens, it will drop out of lock up. You should see a 200-300 RPM increase immediately. If the shudder ALSO goes away, well, there's your problem. If it doesn't, then it's not lock up.

    I agree... there's two main things here. It's either a skip when you are under load, in O/D and towing so you really feel it, or you have a tranny issue. You could stick a scanner on it and see if you have any codes stored which are telling, but just not enough to illuminate the Check Engine Light (CEL). If you don't have an OBD II scanner (they are like $20 on Amazon and work with your smartphone), most parts stores will scan your car for free to pull codes.

    One last thing I would do... check the transmission fluid level, sure. But also, take a nice sniff of it on the dipstick. If it smells like oil, cool. If it smells like burnt coffee or burnt microwave popcorn... make friends with a transmission rebuilder FAST and find out their adult beverage of choice.

    Let us know what you find.
     
    HotelRoyale likes this.
  2. Fbird

    Fbird Member

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    Sep 10, 2017
    Ferndale MI
    You may have to find a shop that's willing to check it out while towing, that being said I've had customers with same complaint. I've seen it be ignition(coil or spark plug), fuel(pump, filter or injector), trans. Even a MAF sensor. So its important to check it when towing. As for the pump it may pass a pressure test but not have enough volume for towing, that being said it would typically get worse with speed not go away.
     
  3. silvermickey2002

    silvermickey2002 Morris County, NJ

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    Sep 11, 2008
    Morris County, NJ
    Our sons 96 F250 7.3 turbo diesel had a tranny problem. He noticed it would shift a little hard when he got on it. But also started to notice when he engaged and disengaged the OD nothing really happened when he was trying to figure out the problem. Then the OD light started to flash. It indicated the torque converter was shot. The cost to do a complete rebuild was $2600. Still cheaper than getting a new truck in that good of condition.
     
  4. DJS12354

    DJS12354 Active Member

    That's the calculation it all comes down to, once you know the problem. Cost to get it fixed vs cost for new truck vs peace of mind as you wonder what the next problem will be. Sometimes it is a matter of "the devil you know"
     
  5. silvermickey2002

    silvermickey2002 Morris County, NJ

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    Sep 11, 2008
    Morris County, NJ
    And if you do buy another truck what problems does it have??? that's why we decided to rebuild his trans. He knows the rest of the truck is solid!!
     
    Novarich likes this.
  6. HotelRoyale

    HotelRoyale Member

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    Sep 23, 2016
    Thank you Generok, DJS12354, and silvermickey2002 for some good advice ... it's at the shop today and I'm waiting on news from the mechanic ... without towing anything, I have my doubts my mechanic will find the cause. Generok's driving test may be my next step if I don't get a definite diagnosis today.
     
  7. Halford

    Halford Well-Known Member

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    Sep 28, 2011
    Santa Clarita, California

    Who would want to steal a cheap heap? heheheh
     
  8. DJS12354

    DJS12354 Active Member

    Here's hoping you get an answer today that both solves the problem and doesn't break the bank.
     
    silvermickey2002 likes this.
  9. tenttrailer

    tenttrailer Art & Joyce - Columbus, O

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    Jul 18, 2013
    Thornville, OH
    Sounds like transmission vibrations. I would get the trans fluid changed .
     
  10. HotelRoyale

    HotelRoyale Member

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    Sep 23, 2016
    I heard from my mechanic ... no codes were displayed when he hooked up his reader so he had no firm diagnosis since there is no problem when it's not towing a load. As I feared, he said I could either keep driving it until it failed, or hook up my trailer and bring it by so we could go for a drive, that means more time off from work to take it to him on a weekday ... I think I will try Generok's test method next and see what happens. That sounds like a reliable test of the torque converter.

    He did check the tranny fluid, it was full and in good shape. When I bought the truck about 2 years ago [but only 2000 miles on it since], I had him do a full tranny maintenance as well as replace all belts, hoses and coolant. The fluid looks, and smells, like new. He did confirm he used an AC/Delco fuel pump when he replaced the pump back in January, so it wasn't a NoNamo replacement pump. I've read a few articles on torque converter lockup failure ... what they describe sounds very much like what I'm experiencing ... feels like you're on a washboard road, comes and goes, usually around 45 mph. [sigh].
     
  11. silvermickey2002

    silvermickey2002 Morris County, NJ

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    Sep 11, 2008
    Morris County, NJ
    Per the trans shop that did our sons trans (as well as other work they have done for us and family)..considering the truck has 161k miles on it, changing just the torque converter is ok, but if the trans goes it will ruin the new torque converter!!! So they recommended starting with a soft rebuild. When they took it apart they had to do a complete rebuild with a bit of new hardware. Yes it was really shot!! That was $2600.00. Truck runs great now, no more hard shifts and MPG went back up. Most of all our son has piece of mind. Trans came with a 1 year warranty.
     
  12. DJS12354

    DJS12354 Active Member

    Okay - No codes, but did he pressure test the fuel pump or do anything beyond check for codes? I'm leaning toward trans problem, but am just wondering re the tests? You could have gone to Auto Zone or similar and they would have done that right on the spot for 0 $
     
  13. Fbird

    Fbird Member

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    Sep 10, 2017
    Ferndale MI
    Fuel pressure isn't all that on a 5.3, volume is what's important. I've seen pumps pass a pressure test but were actually bad. Codes or no codes never scares me. Seeing and interpreting the data as the problem occurs is far more important. It does sound like a classic torque converter problem because you've never had the problem at a higher speed when accelerating.
     
  14. DJS12354

    DJS12354 Active Member

    Any word on the issue?
     

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