I replaced my free hub body due to pedal slippage. I also replaced rear cassette and chain for regular maintenance. Since then the problem started and I replaced shifter and cables as well as rear derailer. I am out of ideas. I know how to properly set high and low range and adjust index. Once the index is set for gears 8-4 or so, gears 3-1 shift too quick and the chain ends up in the large ring when the shifter says it’s in 3 or 2 and the last shifts to 2 or one are incredibly tough as the cable is so tight. If I loosen the cable to allow a smoother shift in gears 1-3 gears 6-8 don’t work together.
The rear cassette and chain is 8 speed, the same part number as previously installed.