Shifting gears feels rough
 

I noticed that shifting gears is becoming "rough" like I have to put more force into sliding it into 2nd or 3rd, etc... especially going into 2nd.
It feels even rougher under WOT, as if I have to yank it into the next gear.
Before the movements used to feel a lot smoother.... now I can feel resistance from the gear walls/doors or whatever their called.
The clutch pedal feels fine.

Are there any possible problems or is it just in my head?

Just drove again and noticed when I'm at a stop with the clutch fully depressed it shifts normally, when I'm accelerating, it gets rough to select gears.

How much play up top do you get with the clutch pedal? It should be less than 1" before feeling resistance. With brakes released, clutch depressed, get in 1st. Does the car "lurch" forward or clunk?

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Clutch pedal still feels fine and stiff. No my car doesnt lurch or clunk forward when going into 1st with brakes off. However there is a clunking NOISE going into 2nd, but after some research on the forums, people say its normal.

The 6 gears have walls that block you from shifting when the clutch isnt depressed. This is where im feeling resistance when the car is in motion, and it is a lot more noticeable going into 2nd and 3rd.

I spoke to a friend at work who has a 2010 Mustang V6 and he says he has the same problem.

Have you switched gearbox fluids yet? That's what I did, and it feels great. It's Redline synthetic. It's not even notchy anymore.

No, I bought the car recently, but its on my list of things to do soon. Flush all the fluids, etc...
Is there anything else that can be causing this? any major worries I should have?

Check to make sure you do have plenty of clutch fluid. Low level or gear lube are the only things I can think of that would change performance under moving and stopped conditions, other than syncros but that is highly unlikely.
How many miles on car?

I think worst case scenario is CSC going out, but I am thinking not. From what I understand that is an instant failure, not gradual.

I would lean with just changing gear lube. You will notice the difference.

Car has 48K currently.

Ive read on the CSC issue and it seems as the key point of failure is in the clutch pedal.
No sure what synchros are exactly.
And how much does a dealership charge to change out the gear oil? I will also do a transmission flush at the same time.

Just checked my fluids, both brake fluids are topped off and clear, so that cant be the issue.
Maybe it is the gear oil, but I really dont want to spend money on that if it isnt going to solve the issue. What if the previous owner changed the fluid not too long ago...

What if he didn't? If you didn't get full maintenance records from the previous owner, just change out all the fluids. That way you can track the maintenance intervals. Diff and tranny fluid shouldn't cost more than $40-50. DIY it, don't let the dealer do it.

The diff oil I can do, but the transmission fluid? is it just as easy? and dont I need a special vacuum or something to flush the system and get ALL the old fluid out?

Nope. Drain and fill just like the diff.

I will probably do the fluids on Monday or Tuesday. I will report back to notify you guys if that fixes my issue.

Redline MT 85 makes a big difference for the transmission.