Question on Manual Transmission Oil Change

I have an interesting situation with my 2005 Cooper S. Not sure if it is one big problem clutch kit or a multitude of smaller problems where a simple fluid change could cure a symptom or two. Occasionally my car refuses to allow me to shift in or out of gear for 1st, 2nd and reverse; double clutching sometimes works, But if I rev to about 2-3k while holding the clutch in it always opens up and allows the shift. The slave was replaced approx 6 months ago as it failed. No grinding, just sticking or refusing to go into gear. I also have slight gear chatter in neutral which disappears for the most part with a pump of the clutch or holding it pressed in.

Pushing 130k miles, shift linkage was replaced around 70k at a bmw shopprevious owner but that isn't a guarantee it didn't go bad again. Can't decide if a fluid change would even be a possibility for remedy on some of the issues or if I would be wasting money doing it should I need to have the clutch/transmission serviced anyway. All of this started happening relatively similar in timing, within a month or so of each other.

Not sure if it is a sign of clutch slipping or another issue, but in lower gears everything seems fine; car pulls just as hard as it did when I bought it 30k miles ago. 5th and 6th gear I get hesitation throughout the RPM range under harder acceleration, or minor yo-yo like symptoms but nothing to the extent of RPMs hiking compared to the acceleration like everyone suggest for a clutch slipping. I can only really describe it as throttle fluttering, but is much more pronounced the hotter it is outside and tends to take on a rotational skipping like sound at a MUCH lower rate than RPM, more along the lines of wheel rotation if not slower originally thought it was belt slip, but replaced the belt with a pulley appropriate one and now I am leaning towards either the vacuum system, pulley, SC, or clutch. Driving normal everything feels fine, it is just heavy accelerating that the throttle feels "fluttery".
No engine lights, which seems to be both a blessing and a curse.

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This post was auto-generated based upon a question asked on our tech article page here: MINI Cooper Manual Transmission and Differential Fluid Replacement (R50/R52/R53 2001-2006) | Pelican Parts DIY Maintenance Article

[Nick at Pelican Parts]

if you are having difficulty shifting, there is no reason to suspect engine parts, focus on the trans. If RPm increases when accelerating and MPH does not, the clutch is likely slipping.

- Nick

[Luccia at Pelican Parts]

I doubt a fluid change will make a difference. When was the last time the fluid was serviced? Typically, with fluid stuff you'd more likely see symptoms of grinding gears. I have a vehicle of mine that has issues getting into 1st gear and a few others at times, including reverse. Sometimes I really have to muscle it in. Definitely a sign that a new clutch is in our near future for it. If you decide the clutch is your issue, check out our awesome clutch super kits as they have everything you'll need for the job while you have access to certain parts. Good luck!

2005 Mini Cooper S Hatchback - Clutch & Flywheel - Page 1