I have a 2004 Jinma 284 that will not go into 4wd. The lever will not move far enough to fall into the 4wd notch. It was always difficult to get in and out but now will not go in at all. Where should I start looking for problem? I don稚 have any diagrams to refer to. Thanks.
Roadworthy
Elite Member
I'd try with the gear selector in different gears or even neutral while attempting to get it into four wheel drive. If it goes in you can shift the tractor into the gear you wanted to use in the first place. Sometimes things have to align just right to work.
RonMar
Elite Member
Under what conditions are you trying to put it into 4WD? mis-understanding the mechanism is usually what gets most users. The 4WD engagement "pawl" on the jinma is a 3 tooth straight cut flat faced component with 3 triangular teeth. Take a pie, cut it into 6 pieces then remove every other piece(kind of like a radiation symbol). This pawl mates with an identical 3 tooth part, facing each other on the end of two separate shafts. one shaft connects down to the front drivetrain and the other connects to the rear drivetrain and the pawls engaging couple these two systems together. Because the teeth are flat faced they must be in perfect alignment in order to slide together. in order to get the two parts to align you must be in motion because of differences in gearing and tire size, the two pawls will turn at slightly different RPMs so they will repeatedly go in and out of alignment while the tractor is moving. Because of these differences, once engaged, the tractor must be on soft ground to allow the tires to slip and release the stored up stress of these differing speeds. 4wd and solid ground = a lot of stress, wear and broken components. it is also why 4WD tears up the ground more...
To engage 4WD, put the tractor in gear, start driving and apply pressure up on the 2/4WD lever. When the pawl teeth align, it will slip into 4WD... Same goes if you are stuck, while in gear with the wheel spinning, pull upward on the 4wd lever till the teeth align and allow it to fully engage. You can push the lever out of 4WD anytime... No clutch necessary, as it is way upstream between the engine and gearbox input it is not part of the equation. This same process is true of any mechanical 4wd vehicle I have ever operated, simply pull the lever. The fact that it will sometimes go into 4WD just setting there is pure luck. Now if the Jinma folks had put points on the front of the pawl teeth, it would probably work al lot easier, but they didn't...
The same 3 tooth pawls are also used on the rear differential lock. While rolling or stuck and spinning, hold upward pressure on the diff-lock lever until the pawl teeth come into alignment. Once aligned, the lever can push them together to lock the rear wheels together... Since the diff-lock lever only pushes the pawls together against a spring and cannot pull them apart, to get the diff-lock to disengage, you sometimes have to try and turn left and right while rolling to take any load off the pawl teeth so the spring can push them apart...
To engage 4WD, put the tractor in gear, start driving and apply pressure up on the 2/4WD lever. When the pawl teeth align, it will slip into 4WD... Same goes if you are stuck, while in gear with the wheel spinning, pull upward on the 4wd lever till the teeth align and allow it to fully engage. You can push the lever out of 4WD anytime... No clutch necessary, as it is way upstream between the engine and gearbox input it is not part of the equation. This same process is true of any mechanical 4wd vehicle I have ever operated, simply pull the lever. The fact that it will sometimes go into 4WD just setting there is pure luck. Now if the Jinma folks had put points on the front of the pawl teeth, it would probably work al lot easier, but they didn't...
The same 3 tooth pawls are also used on the rear differential lock. While rolling or stuck and spinning, hold upward pressure on the diff-lock lever until the pawl teeth come into alignment. Once aligned, the lever can push them together to lock the rear wheels together... Since the diff-lock lever only pushes the pawls together against a spring and cannot pull them apart, to get the diff-lock to disengage, you sometimes have to try and turn left and right while rolling to take any load off the pawl teeth so the spring can push them apart...
aesmith
Silver Member
On the same note if you have difficulty disengaging 4WD because of transmission wind up, turn the steering and go backwards a little to take the pressure off.
RonMar
Elite Member
Exactly!