Down Under

[Elk]

Hi team, My first cruzer age 17 was an fj55, then moved to and 80 and now for the last 12 years a much loved 105 GXL. I've enjoyed taking the family all over Australia, with some epic 4x4 trips. I enjoy working on them as it's a great interest of mine. I have however come with a problem I'm hoping for a little help with. My 105 diesel has a 4 speed automatic transmission. It has just started "surging" between gears when not accelerating around the 60km range. Any idea's. feels like it's electrical to me however I'm not sure. I replaced the fluid and filter with no change. Any thoughts would be appreciated.