1990 nissan hardbody only shifts into 4th and rev gear no other gears, the shift lever moves to the other gears but but truck will not move
Injt: From your description, it sounds serious. If you are describing a Nissan 5 speed transmission, here would be my best guess as to what has occurred. Prior to near total self destruction, these symptoms will show up when counter gear bearings have failed.
At first the transmission will just seem a little noisy, but you probably might not notice that the noise is not present in 4th.
As the bearings deteriorates, the countergear will slowly start dropping and the gears will no longer be running properly aligned.
The noise at that point would be quite obvious. You would hear it in all gears but 4th. With the car at a standstill in neutral with it running and the clutch pedal released to where the transmission is turning, it would sound like a bucket of rocks loose, rattling in the tunnel area of the car. When you depress the clutch in, the noise would disappear. The reason you could run it in 4th is because it is the only gear in which the input shaft and output shaft are locked solid with no relationship to the counter gear. The truck/car can be driven in 4th for this reason. (It doesn't need the counter gear)
Reverse gear is a large gear located at the very center of the transmission next to the Steel center section which you would see sandwiched between the front casing and the tail housing. It is not much more than 1"" thick. Because Reverse is right at that location, even though it does need the counter gear to transfer power, it is the only gear in the transmission which is "SPUR" cut and not helical cut. This design gives it a distinct advantage to operate in a misaligned state with greater spacing. It will still make quite a racket in reverse, but it will move. I am 99% sure that this is your problem. Should this be the case, the transmission has been run far too long to consider repairing. It would probably be scrap metal inside. Find a used one or get a re manufactured one.
I have found that the synthetic gear oils have worked well in our Nissan 300Z race cars we use for road racing. They have basically the same transmission. I am partial to Amsoil and Redline. Both have performed beyond expectations on the track.
I hope I have answered you question.
Mar 20, 2009 |
1989 Nissan Hardbody King