Sticky Manual 5-speed Transmission

2006 mini cooper, 5 speed manual
113 thousand miles
got it in 2010
2 previous owners
never had any previous troubles
learned how to drive stick with the car

stiff shifting, takes a lot of effort to shift to second, 3rd, and fourth, and it’s very difficult to shift 5th and reverse.
–most difficult to shift diagonally–2nd to 3rd, 4th to 5th, 1st to reverse.
–whole neutral area very stiff
then, once in gear, runs just as smooth as it’s always run.
no noise when shifting

has been going on for a couple of months, turning point around when I had an inexperienced manual driver drive the car–they shifted in a very jerky way.

also, hard winter up in maine, but I was always quick to shovel out the car.

Anyone have any suggestions? The manual couldn’t tell us how to check the transmission fluid.

When is the last time the transmission oil was checked/changed?

It’s not particularly likely to be the cause of your problem, but changing the transmission oil couldn’t hurt, and just might improve things.

I suggest you take the car to a mechanic and ask him to change the transmission oil. The job usually costs about $40.

Maybe the clutch is dragging.

First thing I though was the transmission gear oil. Not that the stuff wears out, but many manual transmissions today take ATF instead of gear oil so check the owners manual to find out what oil is used in your MT and then have it checked to see if that is in fact what is in there.

ok4450 also has a good suggestion and it is simple to check, how does it shift with the engine off. If it shifts smoothly with no drag with the engine off, the issue could be in the clutch.

“whole neutral area very stiff”

I suspect a problem in the coupling from shift lever to the trans.
A binding bushing, bent part or dry cable. Something like that.
Find a good independent non-chain transmission shop.

If it’s easier to shift with the engine NOT running the clutch is not releasing.

If it isn’t easier to shift with the engine not running:

1.) if it has an external shifter it needs lubricated.
2.) if it has an internal shifter the transmission is almost certainly low on lubricant.

All responses above are excellent. Did you first notice this when cold weather set in, and does it seem to be temperature dependent? If so, I would suspect that previous owner had the transmission oil changed and the wrong fluid was put in it. I did that to my '81 Toyota once.