Shifter Rod Interference with case | FerrariChat

Shifter Rod Interference with case

Discussion in '206/246' started by jselevan, Dec 7, 2009.

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  1. jselevan

    jselevan Formula 3

    Nov 2, 2003
    1,873
    Came upon an interesting manufacturing defect in the transmission. While inspecting the open transmission with the engine upside down, I noticed that reverse gear was not fully engaging the main shaft gear. There was a subtle but real wear pattern suggesting approximately 75% overlap. While not a critical issue in reverse, it piqued my interest.

    Further investigation revealed that the cinch bolt holding the shift-rod control lever onto the end of the rod was hitting the transmission case when reverse was selected. This interference limited movement into reverse.

    I tried several solutions, including substituting the hex bolt with an Allen socket bolt. This did not solve the problem. Finally purchased another 8 mm (1.25) bolt of same length and torqued it to spec. Then marked the point of contact on the bolt. Removed the bolt and shaved with a stone wheel a bit of the hex head off where contact was taking place.

    Problem solved.

    Jon and Tom - perhaps I can ask that you inspect your case for signs of a contact or wear pattern where the shift-rod control-end cinch-bolt comes close to the case in reverse. Are you experiencing the same issue?

    Jim S.
     
  2. omgjon

    omgjon F1 Rookie
    Owner Rossa Subscribed

    Feb 13, 2005
    3,569
    Spicewood, Texas
    Full Name:
    Jon Gunderson
    I'll check it out, but I didn't notice any wear on reverse gear.
     
  3. jselevan

    jselevan Formula 3

    Nov 2, 2003
    1,873
    Jon - not wear, but a wear pattern suggesting that the gear was not fully mating with the main shaft gear. Inspect the case where the shift rod, when in reverse, closely approximates the cinch bolt. Look for a little scratch or groove suggesting contact. This is the bolt that you removed to withdraw the rod and hammer out the tube.

    Jim
     

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