Question about M20 Transmission adjustment

Discussion in 'U-shift em' started by Iggycat2004, May 4, 2009.

  1. Iggycat2004

    Iggycat2004 1971 Buick GS Convertible

    As some of you know I had a problem with the brand new M20 transmission in my car and it seized up with less than 3 miles on its second test run.

    Question - while shifting into 3rd gear (normal driving conditions) a "grinding" noise was heard loud and clear if I over shifted, meaning pushed the shifter too far forward. If I were to push the shifter too far forward while in third gear cruising at 35 mph it would again, make the "grinding" noise.

    I was told there should be a stop point internal to the transmission on all four gears that would prevent this problem. Multiple people to include guys in the transmission rebuild business said that this should not happen and I should be able to "push the shifter with my foot" and not hear anything abnormal.

    We adjusted the HURST shifter by the book and experienced a catastrophic failure in less than 3 miles. The trans is getting rebuilt at this time and I'm waiting word as to what happened.


    Thoughts?

    Mike

    Iggycat

    NJ
     
  2. moleary

    moleary GOD Bless America

    Did you set up your shifter and linkage with the trans on the bench and set the shifter bolts (stops) that need to be set for the throw from first to second and second to third? It is possible, and again I presume your linkage was not installed upside down on the shift shaft, right?
     
  3. Iggycat2004

    Iggycat2004 1971 Buick GS Convertible

    Moleary,

    Everything was set up by the book and correct, the adjustments were fine and the shifter linkage was also installed correctly.

    Mike

    Iggycat

    NJ
     
  4. Sounds like an endplay issue.
     
  5. Iggycat2004

    Iggycat2004 1971 Buick GS Convertible

    I don't know what the problem was but one thing for sure, it was tight, maybe a little to tight.. When shifting through the gears the initial though was the trans was (new) and would loosen up after awhile. The reverse gear got stuck in gear at one point and the rear wheels were raised in an attempt to loosen it up. It came out of gear after playing with it and you could hear it "click" when it came out of gear - like it got hung up.

    On a good note the trans is now rebuilt from a shop on Long Island NY and I'll be picking it up tomorrow and driving out to Nicks shop in PA for installation. I also bought another (used) original M20 in the event this doesn't work out and come hell or high water, I'm going to the Nationals - with the car.

    As part of my retribution plan if it blows up a second time I'll paint it bright green and use it a bird bath in my back yard with the 26 spline input shaft sticking in the dirt and a bowl welded on top of the TH400 tail shaft. I'll let the birds $hit on it. (frustration levels are high, I'm not kidding)


    Mike

    Iggycat

    NJ
     
  6. Lee Bacon

    Lee Bacon Well-Known Member

    Mike I got my finger's crossed!!! See you @ BG shiftin!!!!!:3gears:
     
  7. Davis

    Davis Moderator

    Mike I will look for you at BG as well as I look forward to seeing you and your car.

    I know I will see Lee there.
     
  8. 70455ht

    70455ht Well-Known Member

    One way or another he will be there! Got a spare trans. just in case.:3gears:
     

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