1968 riviera transmission "knock"

Discussion in 'The "Juice Box"' started by YukonNate867, Sep 16, 2015.

  1. YukonNate867

    YukonNate867 Well-Known Member

    Hey guys so finally got to take my car out for a first drive, was smooth and crisp and then sounds like transmission started to knock, almost sounds like a ujoint hitting the underbody of the car but right in the trans tunnel, thats my best description, it doesnt make the noise in park or neutral or reverse, only in drive/l2/l1... it has spewed atv out the dipstick tube so obviously the vent is plugged, but ive never heard an auto trans make this knocking noise, yes the car supposibly sat for 30 years before hand, but why would it drive perfectly smooth and quiet at first then start knocking like a nasty u joint, inspection cover is off had friend look as reved up, no visual movement between flexplate/converter, doesnt make sound in neutral or reverse... so whats the deal, planetary in trans messed? im lost... just trying to get driving so can cruise it to my work shop 1km away lol, not happening as planned, runs great brake bled nicely just got this stupid trans noise, really sucks..
  2. Briz

    Briz Founders Club Member

    I had a mud dobber wasp plug up the vent tube n a TH400 and it spewed fluid out the fill tube. Never heard one knock before. maybe a cracked flex plate?
  3. CJay

    CJay Supercar owner Staff Member

    Knocking or clunking usually means a bad insulator on the center bearing. Take the drive shaft out and inspect the shaft. While its out, check the CV's and make sure the rear shaft is still in phase. Driveshaft issues are a right of passage for Riviera owners

    BRUCE ROE Well-Known Member

    I would certainly check the drive shaft first, esp if the klunk tracks your speed. But that doesn't explain
    spewing ATV fluid. If that trans is original, the rubber seals inside are on the edge of failure. They can
    be replaced while keeping all the hard parts, but just running them to failure could cause serious damage.

    Bruce Roe

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