On my 2305, I can't tell the difference between 2 and
4wd going straight on dirt or crushed stone. A portion of my driveway is paved and if I forget and leave it in
4wd, on the paving it makes a growling sound with a noticeable vibration. (Kind of a reminder to put it in 2wd.)
It's been the same since new. (Aug. 05)