98 GM 6.5Liter Turbo Diesel

Discussion in 'Trucks and Trailers' started by BillyRgn, Sep 7, 2004.

  1. BillyRgn

    BillyRgn LawnSite Member
    Messages: 248

    i have a 98 gmc 2500 with the 6.5 liter trubo diesel and having a slight worry about the tranney. it seems when the truck is cold the tranney won't grab untill a higher rpm like it won't grab. tranney fluid is full and was wondering if anyone has or had this problem and the truck has about 99,000 miles
  2. naturescaretaker

    naturescaretaker LawnSite Senior Member
    Messages: 854

    My guess is that you have the 4L80E tranny. We went through one of those every 80,000 miles on a 3500HD. Of course it always pulled a 20' enclosed trailer. The new Allison is a great improvement.

    We did find some stuff that you poured in that helped what you are talking about. I will find the name of it and let you know tomorrow.

    UNISCAPER LawnSite Bronze Member
    Messages: 1,426

    You can beef up a 4L80E so it will out perform just about anything. First and foremost, do you have a sizable external cooler at the front of the radiator? That is a must for longevity. It sounds like the pump is starting to go, and if that is going, the torque convertor will be going soon after.
    Ad a shift improving kit and test the electrics when you rebuild and you should be good to go....Oh yeah, plan on a $2,000.00 bill you go to pick it up.

    None of the electric shift trannies are cheap like the old vacuum shifts were to redo. In comparison, we can pull a TH400 tranny, have it up on the bench, stick $350.00 worth of parts in it, and after an 8 hour day have it back in the truck and running. A 4L80E will take the same time to remove, but the parts for rebuild are going to hit you at $1,500.00.00. For something that was supposed to make life easier and save time, the computer is a miserable failure in this instance.

    Good luck with your tranny.
  4. kc2006

    kc2006 LawnSite Silver Member
    Messages: 2,443

    I agree with uniscaper, the cooler and shift improver will help out a lot. Theres a place in my home town that rebuilds race transmissions and I believe he does the newer trans, he would want about 2900 but I doubt that trans would ever give a problem again, the shop is called rossler, he's a pretty famous trans person because he builds them good. Or if you want a cheaper route look on ebay, my friend bought a 4l80e on there for 900 bucks and has had it in his race car for 2 years now with no problem, thats where i'll be buying a e4od for my ford.

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