I have a problem with shifting from one gear level to another, but clutch preasure is still high and the clutch kit was bought last year December. Could the problem be the clutch kit or the gear box? Please advice.

Year make model?? I'm suspecting a manual transmission. Most hard shifts/hard to get in gear are due to a clutch problem. Suspect a worn clutch/defective slave cylinder/defective master cylinder/ improperly adjusted clutch cable just to name a few

you need a new clutch kit and make sure gear oil in level may need refresh and inspect and grease shifter linkage for smother shifting you can update with 42 dizayn's linkage kit for vw it is works great.

bad pressure plate or stuck throw out bearing.

Check your clutch fluid,if empty,then your slave cylinder is bad.

Hello Hannah, I don't believe just yet that your problem is inside your transmission. I would first check the adjustment and condition of your clutch. If it were an internal transmission problem it would probably be with one gear ,not all of them. You aren't grinding fourth gear because it is possible to shift into fourth gear without using your clutch if your RPM's are high enough. If you are really lucky you will only have to adjust the clutch, and if your not so lucky you may have the go for a new clutch, preasure plate, and throwout bearing. In any case I would like to know how you make out, please contact me and GOOD LUCK.

the high pitch noise leads me to believe a problem with the hyudraulic clutch. Have you checked the level? also with manuals you dont have tranny fluid, you have gear oil; which is very unlikely that needs changing

problem may be the thickness of your clutch disc and preasure plate faces

on the older style blazers the fan clutches did fail and would often be misdiagnosed as shifting problems as the clutch engaged and disengaged.... also a hard 1-2 shift can be due to your vehicle storing a transmission fault code in the ecm... some transmission fault codes will put the transmission into a fail safe or limp mode in which it engages high line pressure .... this can cause your hard 1-2 shift and will feel normal most of the time other than that. high mileage on the transmission fluid may also require it to be flushed and have the filter kit replaced

It is hard to say from your description what the problem is ... could be linkage issue ... could be trans is going as is with the other poster ...
Losing overdrive. Clutches (bands/clutches) have had it. Be careful driving without that top gear ... doing too high a speed without the appropriate gear causes extra stress on your engine that could accelerate further problems. Try to do only driving at a low enough speed that the top gear is not missed ... will help the vehical last as long as possible.

Sounds like the wrong pressure plate. I got a kit from Autozone and it was the wrong pressure plate. My old one was obviously thicker. With the new pressure plate, the shift fork was almost at full travel before any resistance. That's no good. I had to pull the transmisssion again and use my old pressure plate. Luckily, it was in good condition. Then, the clutch slack was easily adjusted and works great.