Hi all,

My 99 Suburban's tranny is starting to act up (4L60e). Under heavy acceleration there is a 200-300 bump in RPMs on the 2-3 shift. I read that this "flare" is a common problem with these trannys. The trans has been rebuilt once before at about 160k, she now has about 205k on her, but the shop that did the rebuild is no longer in business. The funny thing that this only happens on the upshift. When in "3" and you put it to the floor, the downshift is as strong as ever and then will shift back into third with no problems. When it does happen, it doesn't feel like a slip, the flare is usually quick to happen.

Is there any other input to what this could be? Should I change the fluid and filter? If it comes down to needing to tear into the tranny I might as well have them go through everything and put a shift kit in it as well.

Thanks,
Cole.