78 Pace Car Transmission Problem - NCRS Discussion Boards

78 Pace Car Transmission Problem

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  • Matthew S.
    Expired
    • August 31, 2005
    • 64

    78 Pace Car Transmission Problem

    I have a 78 Pace Car with 1300 miles on it. It's an L48 with a 4 speed. When I bought the car last summer with 1100 miles on it the transmission worked fine. However, last fall before I put the car away for the winter it developed a shifting problem. The transmission works fine when upshifting in all gears, however, when downshifting from 3rd to 2nd or 2nd to 1st the gears will grind if I try to downshift.

    Also, when the car is in 2nd gear and and I rev up the engine (to around 3000 rpms) the shifter vibrates badly. If I disengage the clutch and let the car coast the vibration goes away completely.

    Here's what I've done so far:

    - changed the transmission fluid
    - checked the clutch free pedal travel
    - checked the clutch spin down time and it's OK

    My questions are:

    1 - could this be caused by misaligned linkage?
    2 - are there any other adjustments that I'm missing that I could check?
    3 - at the Marlborough regional last year I got a Bowtie signoff on the car so I'm planning to bring it to Charlotte in July for Bowtie judging. Assuming that the transmission needs some internal work that will require it to be removed from the car would I be better off leaving it alone until after it's judged in Charlotte? I don't plan to drive it until I get this problem fixed.

    Any help is greatly appreciated.
  • Dick W.
    Former NCRS Director Region IV
    • June 30, 1985
    • 10483

    #2
    Re: 78 Pace Car Transmission Problem

    Just fer grins, what weight lube did you put back into the transmission??
    Dick Whittington

    Comment

    • Matthew S.
      Expired
      • August 31, 2005
      • 64

      #3
      Re: 78 Pace Car Transmission Problem

      Dick - I used 80W-90.

      Comment

      • Tom R.
        Extremely Frequent Poster
        • June 30, 1993
        • 4099

        #4
        Re: 78 Pace Car Transmission Problem

        Hey Matt

        I'm curious what's the VIN on your Pace Car and where did you pick it up from? Seems like I saw one a couple of years ago at Carlisle with about 1100 miles...nice. It may have been the one I got plenty of photos for reference. I'm including a link to an article published in the Restorer last year on 78 four speeds for your reference. As you study and enjoy the car, you may be able to fill in the blanks at the end of the article. Enjoy!

        Tom Russo

        78 SA NCRS 5 Star Bowtie
        78 Pace Car L82 M21
        00 MY/TR/Conv

        Comment

        • Edward J.
          Extremely Frequent Poster
          • September 15, 2008
          • 6942

          #5
          Re: 78 Pace Car Transmission Problem

          Matt, sounds like a internal problem with your transmisson,I know the car has little mileage, but may require taking out the transmisson to do some poking around inside, maybe a support bearing problem (input /output shafts)or possiable blocking rings, since you'll be going through bowtie judging, I would wait until your through, don't want to disturb to much.
          New England chapter member, 63 Convert. 327/340- Chapter/Regional/national Top Flight, 72 coupe- chapter and regional Top Flight.

          Comment

          • Matthew S.
            Expired
            • August 31, 2005
            • 64

            #6
            Re: 78 Pace Car Transmission Problem

            Tom,

            My car is VIN # 902535. I bought it at Carlisle this past summer. It may have been at Carlisle a few years ago. The car was originally from PA.

            Thanks for the article. I'll read throught it and send you any info I find on the car.

            Matt

            Originally posted by Tom Russo (22903)
            Hey Matt

            I'm curious what's the VIN on your Pace Car and where did you pick it up from? Seems like I saw one a couple of years ago at Carlisle with about 1100 miles...nice. It may have been the one I got plenty of photos for reference. I'm including a link to an article published in the Restorer last year on 78 four speeds for your reference. As you study and enjoy the car, you may be able to fill in the blanks at the end of the article. Enjoy!

            http://www.hunt4cleanair.net/Articles/fourspeeds.pdf

            Comment

            • Joe L.
              Beyond Control Poster
              • February 1, 1988
              • 43219

              #7
              Re: 78 Pace Car Transmission Problem

              Originally posted by Matthew Surette (44394)
              I have a 78 Pace Car with 1300 miles on it. It's an L48 with a 4 speed. When I bought the car last summer with 1100 miles on it the transmission worked fine. However, last fall before I put the car away for the winter it developed a shifting problem. The transmission works fine when upshifting in all gears, however, when downshifting from 3rd to 2nd or 2nd to 1st the gears will grind if I try to downshift.

              Also, when the car is in 2nd gear and and I rev up the engine (to around 3000 rpms) the shifter vibrates badly. If I disengage the clutch and let the car coast the vibration goes away completely.

              Here's what I've done so far:

              - changed the transmission fluid
              - checked the clutch free pedal travel
              - checked the clutch spin down time and it's OK

              My questions are:

              1 - could this be caused by misaligned linkage?
              2 - are there any other adjustments that I'm missing that I could check?
              3 - at the Marlborough regional last year I got a Bowtie signoff on the car so I'm planning to bring it to Charlotte in July for Bowtie judging. Assuming that the transmission needs some internal work that will require it to be removed from the car would I be better off leaving it alone until after it's judged in Charlotte? I don't plan to drive it until I get this problem fixed.

              Any help is greatly appreciated.
              Matt------


              By the way, the cast iron case "Muncie" is not a transmission that you want to need internal parts for, so let's hope you don't need any. I don't know of any current manufacturer of major internal parts for these, although I expect that things like bearings, synchro rings, and small parts are available. I'd check with a source like Larry Fisher or Ed Hartnett.
              In Appreciation of John Hinckley

              Comment

              • Tom H.
                Extremely Frequent Poster
                • December 1, 1993
                • 3440

                #8
                Re: 78 Pace Car Transmission Problem

                Originally posted by Matthew Surette (44394)
                Tom,

                My car is VIN # 902535. I bought it at Carlisle this past summer. It may have been at Carlisle a few years ago. The car was originally from PA.

                Thanks for the article. I'll read throught it and send you any info I find on the car.

                Matt
                Your car is a nice one ! It was parked right next to my spot in Carlisle. Hope you get the issue cleared up without too much trouble.
                Tom Hendricks
                Proud Member NCRS #23758
                NCM Founding Member # 1143
                Corvette Department Manager and
                Specialist for 27 years at BUDS Chevrolet.

                Comment

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