Yesterday my 2000 GTP started getting a little heavy going into reverse from neutral or park. No bad noises or anything, just a much heavier than usual thump. I changed the filter and fluid today as it was in need of it, and that didn't seem to do much of anything for it. The magnet had the usual sludge, but nothing out of the ordinary, and definitely no chunks or free floating metal in the pan. Going into drive, and through all the gears while moving are normal.
What might I be looking at, or what should my next steps be to determine the problem? Recently I have dropped the subframe(heavier shift was not apparent afterwards). Also just two days ago I finished replacing the struts. Is it possibly a bad axle? Passenger side is new. Driver side does click on a fully turned wheel so it will need to be done soon, but it doesn't have any wobble or shuddering while driving. Lower motor mount is also brand new, trans mount is about a year old.