gears not working
 

My car won't engage the clutch properly so it's very hard for the car to take off and it's difficult to change gears. I hired a mechanic to come and look at it and he said that the clutch master and slave cylinders aren't leaking at all so they couldn't possibly be the problem. He said there must be something wrong inside the clutch but I just had it upgraded to a heavy duty clutch 10,000Kms ago. Thoughts?

The second half of your sentence does not disprove the first, the "but" is ill used.

Less pedantically, the fact that you got an upgraded clutch a few miles ago means absolutely fuck all to the diagnosis.
Both you and the mechanic apparently agree this is a clutch (instead of transmission) problem and the only exterior components seem to be in working order, so what else is left but the flywheel/clutch/pressure plate?

The car wants what it wants, when it wants it and neither yours nor the lamentations of all your women will assuage the need.
No matter what, seems the trans is coming out soon, boyo.

Despite a lack of brake fluid leaks from the clutch hydraulics, does the clutch slave cylinder extend completely when the clutch pedal is depressed? This would definitely be the first place to look.

Besides this, some "heavy duty" clutches can bend the stock clutch fork or break the pivot ball it rides on. ACT extreme pressure plate comes to mind. There are some potential fixes for this, but all of them require some ingenuity and fabrication skills/ tools are your part, and the trans or engine would defintely need tk come out.

I don't think it will be the clutch itself.

Yeah, he did check this. He got me to push in the clutch while he was under the car looking at the clutch cylinder but I don't think he was too certain about how much it should have been moving. I don't think it was moving much from what he said.

But he basically told me that the only way for a clutch cylinder to be bad is if it's leaking and the fluid tank was completely full with no visible signs of leakage anywhere.

WHAT?

The Slave sits ABOVE the engine on top of the bell housing close to the firewall..so if this guy was UNDER the Car then he was checking out NOTHING.(bullshitting you).

I'm with scathcart. I believe something is bent or deformed. Your problem of difficult getting it in gear tells me the clutch isn't fully disengaging. Maybe try bleeding the system again just to be sure.

yeah actually that's probably where he was. I couldn't see him. He showed me where it was behind the tmic.

you can bleed the clutch cylinder fluid? I haven't tried that yet. Is it difficult?

Maybe, but not necessarily.
This past week I've spent a lot of time beneath my car working on the gearbox (way too much time, honestly) and found the slave cylinder pretty easy to access from below the car, reaching up. It would be particularly simple to feel the release lever move as the pedal was depressed.

It's just like bleeding brakes, not difficult at all.
I agree with your tech that it's probably not the hydraulics but disagree that it couldn't be without evidence of leakage.
And speaking of leakage...have you checked the rear of the clutch master from inside the car? That's a very common failure point and you won't see anything from the bay as it'll leak inside the firewall.
It's a possibility...

the test to see if its a hydraulic problem or mechanical is simple.

if the car shifts ok with the engine off, its likely to be hydraulic.

if its the same with the engine off, then its probably mechanical

Check for hydraulic leaks. Crawl underneath the dash with a flashlight and look above the clutch pedal, make sure it's not wet or leaking fluid. Inspect the clutch master cylinder (plastic reservoir on drivers side firewall). Follow the hose running from it, it leads to the slave cylinder on the top of the transmission. Feel around the slave for leaked fluid.

If everything seems alright, bleed the hydraulic fluid. On the slave cylinder, next to where the hose from the master cylinder connects, there is a bleeder valve.

You need:
1. 8mm open box wrench
2. Clear flexible hose (1/8")
3. Small container, partially filled with fresh brake fluid.
4. Mom

Attach clear hose to bleeder valve - make sure it's on tight. Submerge the other end of the hose in the container of brake fluid. Make sure the hose stays submerged, this is imperative to your success. Have mom sit in the drivers seat and await your command. Attach the 8mm wrench to the bleeder valve. Turn it loose about half a turn, and tell mom to press the clutch pedal down and hold it. Fluid and air bubbles will shoot through the hose and into the container. Re-tighten the bleeder, and then have mom let up on the clutch pedal. Repeat the process. Each time, air bubbles will escape from the system. Keep the master cylinder reservoir filled with brake fluid, don't let it get too low. You'll be finished when you stop seeing air bubbles coming from the bleeder valve.

Of course, if the hydraulic fluid isn't the problem, you might have simply bent your clutch fork or broken the pivot ball in the transmission bell housing. Surprise! Good luck.