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Clutch V6 Shaking Most In Reverse When Hot

Discussion in 'Early CJ-5 and CJ-6 Tech' started by juffer, Oct 25, 2018.

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  1. Oct 25, 2018
    juffer

    juffer Juffer Sponsor

    Netherlands
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    Hi guys,

    I did my clutch a few years ago and did drive about 2000 miles in total over these years. With a centerforce presureplate. Now when cold it is 95% ok and not shaking , but when hot it is shaking all over. there is no oil leak.

    I will get the clutch out and see, but I am wondering if there is some experience here about the cold/ hot case.
    I have the new clutch ( luk) on the shelf

    Could the flywheel be the problem, getting out of shape when hot?

    Tanks in advance
     
  2. Oct 25, 2018
    Walt Couch

    Walt Couch sidehill Cordele, Ga. Sponsor

    cordele, Ga.
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    I would look at the stay cable. That is a cable that is connected from the bell-housing back to the trans cross-member. When cold, the rubber in the mounts may be stiff enough to support stability but after warming up they become soft. JMO
     
  3. Oct 25, 2018
    PeteL

    PeteL Member Sponsor

    Hills of NH
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    x2.

    Especially in reverse, excess movement in the clutch linkage can start a feedback loop of resonant shaking.
     
    Last edited: Oct 25, 2018
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  4. Oct 25, 2018
    Focker

    Focker Ran when parked... Runs while moving. Staff Member Sponsor

    Tri-Cities WA
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  5. Oct 25, 2018
    juffer

    juffer Juffer Sponsor

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    Sorry, Don't have a "Stay cable" on my 69. Is this original on a dauntless? . All crossmember rubbers are new . But indeed in reverse it is horrible. Clutch linkage looks and feels OK.

    Well, I have to get it out and let the flywheel machined too.
     
    Last edited: Oct 25, 2018
  6. Oct 25, 2018
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    Beyond what has already been mentioned...

    Did you have the flywheel surfaced when you did the clutch?

    Any possibility you used a little too much grease on the transmission splines that go into the clutch disc upon assembly?

    There's a chance your trans leaked just enough oil out of the nose to wet your clutch, but not enough to drip.

    Any of those will cause a little bit of chatter that will only be magnified by a less than perfect driver's side motor mount. The reason it will be felt greater in reverse is because the T-case has a mount off to the passenger's side that absorbs the counter-clockwise torque forces that are countering the clockwise drivetrain rotation when going forward.

    In reverse, those forces are reversed, and there is no mount like that on the driver's side (except for the stay cable, which I still debate the value of... but I digress...). All of the torque your jeep is creating and sending through the driveshaft is equally trying to spin your engine in the opposite direction. If the driver's side motor mount has a tear or has too much elasticity, or your mount is broken, it will allow the engine to hop in the bay.

    So to recap, something is causing the clutch to grab, and something is allowing that grab to move your engine excessively.
     
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  7. Oct 25, 2018
    Daryl

    Daryl Sponsor Sponsor

    Bonney Lake, WA
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    Many T14 V6 Jeeps cannot back up at all with out the stay cable in place.
     
  8. Oct 25, 2018
    juffer

    juffer Juffer Sponsor

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    is the staycable on a v6 69 original?Where can I get one , or how to make one? Thanks learning everytime!!
     
  9. Oct 25, 2018
    Hellion

    Hellion Rust covered & junky

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  10. Oct 25, 2018
    Brislin06

    Brislin06 New Member

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    I have a 69 cj5 with the v6 mine used to do it. I could not find any bracket or evidence of a stay cable on it. I ended finding out that it was the motor mounts I replaced both of them which were bad and all gone. Still don’t have a stay cable.
     
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  11. Oct 25, 2018
    Beach66Bum

    Beach66Bum Member Sponsor

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    I had to go out and check my ‘66 with the v6. It has the fork and bracket for the stay cable, but it’s missing. I haven’t had any shudder but will order a new replacement cable.
     
  12. Oct 25, 2018
    PeteL

    PeteL Member Sponsor

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    That makes no difference. The point is the engine and transmission moving under load, relative to the frame and body. This acts upon the clutch linkage which bridges those two areas, and causes it to set up a self-aggravating feedback, since its action makes the engine versus frame motion even worse.
     
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  13. Oct 26, 2018
    Hellion

    Hellion Rust covered & junky

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    I think its official nomenclature is "cable, engine stay assembly" and looking all over the web it's on most every CJ-5, CJ-3, CJ-2, M38A1, M38 et al, going back to the MB/GPW of WWII.
     
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  14. Oct 26, 2018
    juffer

    juffer Juffer Sponsor

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    Still can not find a new one on the internet. And when the clutch linkage is the problem. Say that is has a lot of free play in the clutch linkage so that movement front or to the rear does not engage or disengage the clutch , how can it than cause the vibration. I Have read all the posts. But this question stays in my mind un answered.
     
  15. Oct 26, 2018
    juffer

    juffer Juffer Sponsor

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    Here what I found on a cj3 page. Nothing about preventing wheelhop. (looking ast the motormounts of a wilys I can imagine this is needed) Mine is vibrating when hot. When cold there is no problem. still think it is the clutch and flywheel to cause the vibration because 500 miles back it was OK and never had a Stay cable




    On page 34 of the Maintenance Manual for Willys Model MC-38 (a military sibling of the CJ-3A) it is explained. Here is what the manual has to say...
    "The engine is prevented from moving forward on the rubber mounting, when a sudden stop is made, by the engine stay cable which is attached to the left side of the flywheel bellhousing in the front and to the frame cross member at the rear. The length of the cable is adjustable to provide correct tension through a threaded end mounting. Do not overtighten the cable. It should be adjusted to provide 1/2" up and down movement by thumb pressure.
     
    Last edited: Oct 26, 2018
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  16. Oct 26, 2018
    1967 CJ5A

    1967 CJ5A Mike

    Southern Indiana
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    What kind of clutch linkage do you have? If you have a cable clutch, the movement at the engine and at the pedal are isolated, which prevents the feedback that the stay cable is there to prevent. I have a cable clutch on my '69 and there is not even a place for a stay cable to mount.
     
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  17. Oct 26, 2018
    Focker

    Focker Ran when parked... Runs while moving. Staff Member Sponsor

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    Here is what is weird about mine. The first drive of the day is fine, no hop, no skip nothing. After the jeep has been sitting (up to 8 hours) and I go to drive it home. It hops, I replaced the motor mounts thinking that was the issue, but it still does it.

    Edit: This happens when going forward.
     
    Last edited: Oct 28, 2018
  18. Oct 26, 2018
    PeteL

    PeteL Member Sponsor

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    Oil on a clutch will cause chattering. Maybe some kind of slow leak when hot?
     
  19. Oct 26, 2018
    ITLKSEZ

    ITLKSEZ Volvophilic

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    A cold oil-tainted clutch will act differently than a hot (or even warm) one.

    The V-6s have motor mounts that are close to each other (compared to other engines) and are soft and flexible, even when new. I can only assume the Jeep/Buick engineers did this to calm the vibrations of the potato-potato. The downside is, any imperfections in the clutch action will transfer directly to the mounts. With its heavy crank and flywheel, the rotating mass of this engine is about 1/3 its total weight. A jerky clutch action will compound in no time through the soft mounts.


    There's always the cheap redneck fix! :D Every 225 I've seen in a race has either done this, or has completely rebuilt the mount design to something more robust. Just for kicks, try clamping down (or using a ratchet strap on) the driver's side mount and see if the issue goes away.

    [​IMG]
     
    Last edited: Oct 26, 2018
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  20. Oct 26, 2018
    juffer

    juffer Juffer Sponsor

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    I have the stock linkage, no cable. And it has always been perfect. I did some offroading and the car was out of action for a year and now running more than ever. I asume the flywheel has to be serviced with a new clutch. ( the linkage can impossible engage or disengage the clutch when moving front or rear. it is made for movement. I can not imagine that movement in what side will change the leverage. ( try it with a model from small pieces wood or so))

    I even had new crossmemeber rubbers with a third one extra on the right side to the chassis. But I wil probably try the chain . I will keep posting till I have the solution. Thanks for the input. Great forum to learn
     

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