So i never too the range rover too the west coast, sent my pretty much lifelong mate and landy specialist, some videos of what it does after trying for like half hour to get the right bit of road and gear and throttle input, and the mrs over my shoulder filming the dials only does it in drive not sport or manual, he still struggled to see what i could, flared 3rd gear change cold, 5th when warm under the right conditions 30 40ish % throttle like right before the point it should go back too 4th it gains speed but the rpm pulses up (no flutter) but its like it gains 50rpm a time, rev counter moves like a clock seconds hand rather then smooth if you understand
im convinced its mabye torque converter,
Iv got 4 options
1, Run it and see it actually get bad enough to pinpoint risking the gearbox
2, Throw a torque converter in and tube seals and bridge seals and filter and fluid and hope for the best
3, iv got a spare 4.2 engine and box on its way out of the black one i sold him years ago so send that gearbox away to be reconditioned and new torque converter as the mileage is only 5k less then my range rover
4, pull it apart break it and buy another (my least favourite option)