I’ve got a 2002 eclipse rs 2.4l and my shifter doesn’t go back to center by itself if I move it left or right and when I put it into gears it sometimes is hard going into the gear I replaced the fluid with Amsoil fluid last year sometime as well there was no metal shavings at all on the plug or in the fluid so I assume the tranny is in good condition. It seems to be better when I drive it for a while or if it’s warm out but it will still go into gear a little hard sometimes regardless. Could the problem be the cable bushings? I’ve lubed the cables a few times which helps somewhat for a month or 2. I also replaced the master and slave cylinders with direct parts from Mitsubishi.
A car that refuses to shift or go into gear easily is trying to tell you something is wrong and in most cases the culprit is the clutch or transmission. Transmissions are very complicated and have many moving parts, ignoring a hard to shift issue can quickly spiral into a very expensive transmission repair.
If your shifter actually feels different you need to try and figure out why first. I would unhook the cable from the shift arm on the trans and then test the shifter movement to see if its the cable. At that time go to the trans shift arm and move it around with your hand to see if it can move up and down as well as fore and aft… See if the movement feels normal, it must move relatively easily with positive feel. Be sure nothing is obstructing the movement of that shift arm on the trans and notice any lube points on it as well as plastic bushings associated with the shift linkage… I think you may find something here.
Changing your trans gear oil can sometimes produce unwelcome results due to viscosity. I had a similar problem with my 6sp in my GTi. I changed the trans lube with aftermarket lube… turns out my trans did not like that new lube and it was a known issue caused by the aftermarket lubes viscosity properties. When cold it would be sluggish and just not a good feel to it…when hot it was ok… but I dropped the new lube out…and bought the factory VW gear oil and it was noticeably thinner despite the numbers on the bottle for viscosity. It instantly fixed the issue.
Viscosity numbers should be self explanatory…but for some reason one makers 90W oil is not the same (does not flow the same) as another makers 90W. I have noticed a big disparity in this area actually. So this may be playing a part in your issue. So do those tests outlined above and if they check out and are free moving etc…it may be the properties of that Amsoil.