Clutch adjustment automatic

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Joshi, Feb 6, 2022.

  1. Joshi

    Joshi Bobtail Member

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    I have Freightliner cascadia 2019 automatic. From few weeks when ever i stopped on lights or truck in gear and i used pedal break my truck tries to move or feeling like pushing for driving. It has 640k kilometre.
    What could be reason
    Or
    If it is due clutch ? Then does automatic clutch can be adjusted?
     
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  3. God prefers Diesels

    God prefers Diesels Road Train Member

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    I am not going to pretend to answer your question. But I will say in a semi truck, and "automatic transmission" is actually a manual transmission with computer-controlled servos that actuate the gears. So yes, there is a clutch. Yes, you can adjust it. Adjusting it should also make you smoother when you're trying to back up.
     
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  4. Oxbow

    Oxbow Road Train Member

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    I honestly have no experience or knowledge of automated trans in class 8 trucks, but I thought there was a pretty defined distinction between auto-shift manuals and automatic trans, and that both were used (eaton autoshift 18spd versus Volvo, Freightliner, and Allison automatics that must have a torque converter).

    Again, I know nothing about them, but isn't there a true automatic versus an automated shift manual?
     
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  5. God prefers Diesels

    God prefers Diesels Road Train Member

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    Same here. If it's got a torque converter, you could potentially build a nasty transmission. Otherwise, it's just a regular "ole manual" controlled by a computers.
     
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  6. Hammer166

    Hammer166 Crusty Information Officer

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    Allison is still the only slushbox. All the others are AMTs. There's been various clutch handling ideas. One of the older Eatons used some sort of centrifugal actuation, but I believe everyone has settled on actuators as the electronics have caught up.

    I've got an Ultrashift Plus, and it's like the very best driver on the clutch.

    As to the OP, he's likely got some sort of actuator or it's linkage issue. A worn clutch goes the other way and releases further than needs to as it wears. He's describing clutch drag, and it dawns on me he could have a spring out the plate. No reason that can't happen to an AMT just like a manual.
     
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  7. Oxbow

    Oxbow Road Train Member

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    Thanks for clearing that up!
     
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  8. jason6541

    jason6541 Road Train Member

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    The DT12 is a air actuated clutch. Do you have air leaks?. You may have the actuator leaking, you know when a truck has the DT 12 you hear it make a weird burping noise and hiss when it shifts. I know that you can take it to dealer and have a clutch relearn program run.
    Been many years since I screwed with them.

    If your air system is not maintained properly it will effect the transmission, Volvo transmissions are heavily reliant on air as well.
    Amazes me the amount of trucks that don’t receive proper maintenance. Not saying you don’t maintain your truck. But quite a few don’t.
    Air system is used for emissions, drive train actuators, brakes and switches. But yet the most neglected system on a CMV. Cheap and easy to maintain is the perplexing part.
     

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  9. Joshi

    Joshi Bobtail Member

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    Thanks everyone
     
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