International 6 plus shifting

Discussion in 'Trucks and Trailers' started by bearmtnmartin, Oct 2, 2011.

  1. bearmtnmartin

    bearmtnmartin LawnSite Senior Member
    Messages: 342

    I just bought this truck. Its a 1998 with a 6 plus 1. Its the worst shifting tranny I have ever operated, and I have well over a million miles in heavy trucks. I am wondering if a fork is bent. Or is it a synchro with all the cogs worn out? Three of us have tried to drive it smoothly and no go. I'm getting tired of sitting in intersections trying to find a gear.....And forget about downshifts.

    Also wondering where this engine likes to run. Its a DT 466.

    Thanks for the help

    International dump unit 3 (2).jpg
  2. ecurbthims

    ecurbthims LawnSite Senior Member
    Messages: 493

    the six plus is a very reliable tranny ,easy to shift as well .I would yank it out and figure it out before something lets go and ruins what is still good ,but it sounds like you have a damaged fork .On a side note ,if its too expensive to repair,these trannies are available cheap as hell from fleets getting rid of school buss's ,you can often buy a whole bus for $500.00 .
  3. westcoh

    westcoh LawnSite Senior Member
    from Alberta
    Messages: 313

    Sounds like something's wrong. I have a 97 with the 6 plus 1 and no real problems with shifting / downshifting and I'm not the most experienced truck driver out there. Only thing I've really noticed is sometimes after coming to a stop it's difficult to get into 1st gear.
  4. sbrem

    sbrem LawnSite Member
    from Vermont
    Messages: 14

    Although I have never driven a 6 plus 1, I have occasionally had this problem with other transmissions and I find if you stick it in a higher gear first and then go right back to first, things will line up an it will slide right in.
  5. bearmtnmartin

    bearmtnmartin LawnSite Senior Member
    Messages: 342

    I've settled on a bent shifting fork. It hasn't got any better. Its as if there is an obstruction in front of every gear.

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