When a car won't go over 40 MPH and won't change gears right could be the start of many problems. The most common problem would probably be the filters.
Gears are a toothed machine part, such as a wheel or cylinder, that meshes with another toothed part to transmit motion or to change speed or direction.
your syncronizers in the transmission are worn out in 5th gear. there what make the gears line up in speed so you can change them smoothly
there are 2 marks on the gears you have to line them up
BAD clutch slave cylinder, wore out clutch and pressure plate.
My best guess would be a leaking slave cylinder. You may have to pull the transmission to access it.
4:10 or 4:11 gears.
If speedometer itself is working then gears inside the assembly are damaged.
Unfortunately, you can't change gears on bikes in HeartGold.
A faulty slave cylinder will not cause your clutch to slip. The slave cylinder is made up of a housing and a rod. The rod pushes the throwout lever against the throwout bearing, that push the teeth on the clutch housing causing the clutch to disengage and you are allowed to shift the gears. When a slave cylinder fails it makes it difficult for you to shift gears. When it completely fails you will not be able to change gears at all for the most part. I sincerely hope this helps you. www.subarushirt.com The only exception would be if the slave cylinder managed to leak fluid onto the clutch disc.
You have to change the gears
`By disengage I assume you mean you can't change gears or get it out of gear. You may be able to change gears if it is not running. If this is so, it is one of several possibilities. You have a hydrolic clutch. The master cylinder can be empty, or more likely, the slave cylinder located on the transmission housing is bad. You should be able to see the slave cylinder. Have someone push the clutch in and see if there is any movement in the slave. The clutch disc can be screwed up, but that's a long shot.
Not 100% sure on an excel, but where is it leaking? If your car has no clutch fluid then you will not be able to change gears, I would check the seals on the master/slave cylinder, as that is one of the more common places clutches leak.