300Zx will not shift out of 5th gear
Dear javatrader: There are very few solutions to this problem. The fact that you had mentioned 5th & Reverse, tells me that you problem is has two possibilities. Both relate to the same component.
The shift fork for Fifth gear and reverse are the same as well as the hub which the fork fits over.
When you Move the stick shift, it moves one of 3 rails in the transmission of which one is 5th and reverse. The hub is what locks the transmission in gear. The gears are what are referred to as synchromesh. This means that when you shift from gear to gear, it makes it possible to easily make the transition without the gears grinding while the car is in motion. The synchros are in fact, kind of a "BRAKE" for the gears so that when you go to shift into that gear, the synchronizing ring, slows the gear down enough to match the speed of the counter gear allowing it to engage with it, without grinding. As the hub slides into gear, there are spring loaded "KEYS" which are small pieces of steel about 1/2 inch long, 1/4 inch thick and 1/4 inch wide with a little hump in them to push up into a small cavity machined into the hub when it slides over it, thus locking the gear into place until you pull the stick to move it out of place. If a key pops out, it could cause the gear to stick, not allowing you to pull the hub back because the key has popped out at an angle which prohibits the hub from sliding over it.
Another possible senario: The fork is secured to the shift rail with a part called a "Roll pin". If this part shears, the car will be stick in what ever gear it was in at the time the pin sheared. If the pin shears, the stick will still move out of 5th gear position but the transmission won't.
This problem, unfortunately is not one a layman can fix. This is best left to a professional.
Good luck......If you are pleased with my answer, please write in, that you are satisfied with my answer. I am new in this "FIXYA" group and need more people responding to work my way up the ranks.
on Nov 10, 2014