Jinma 284 diff lock won't disengage

[jinmajoe]

I just bought a 2007 Jinma 284 with 35 hours on it. I'm having trouble with the differential lock not disengaging, anyone know anything about this? Also after I've been operating it for maybe an hour it wants to stick in first gear, even with the engine off and clutch in still doesn't want to come out. Also doesn't want to go into 3rd gear. Shifter seems unusally loose, maybe could be the problem. Any suggestions would be appreciated. Kind of discouraging since I just got it but hopefully can get it straightened out.

Ivan

 

[kthompson]

I would first check the oil level with all those issues. But on the rear differential not wanting to release I have had to stop and back up just a little to allow the tension so it could release. On the gears is 1st an

 

[jinmajoe]

thanks for your reply, however I only received part of it. I didn't get anything on the the gears. I've checked the gearbox oil and it's full. I was thinking, since the tractor is a 2007 but only has 35 hours on it, it must have been sitting for a long time. Maybe the gear box is gummed up. Maybe I should try running a light weight oil in it for a while or even diesel and then flush it out and fill it with new oil.

 

[quicksandfarmer]

Back then Jinmas were shipped from the factory with "transport" oil in the gearbox, differentials and engine. You were supposed to drain it, flush it with kerosene, and replace with the proper fluid before doing anything. That might not have been done if it only has 35 hours. All your problems sound like they could be just poor lubrication.

The differential and transmission share an oil supply but have separate drains. I would drain both and assess what comes out. If it looks suspect then flush it.

 

[jinmajoe]

Thanks, I'll do that. Tractor has backhoe unit on back so I lifted the rear with the outriggers and worked the rear wheels back and forth to try and disengage the diff lock but still didn't work, am thinking about removing the top cover on the gearbox under the seat, maybe I can get in there and disengage the diff lock manually

 

[kthompson]

Try really oiling the linkage to all points in it before you open it up. Those amount of hours for that age the linkage could just need a good oiling.

 

[jinmajoe]

First of all thanks to everyone for helping.

With the diff lock problem turns out that the fork shaft that disengages the diff lock has an adjusting bolt and lock nut on the end of it that the engage/disengage lever rides on outside of the gearbox case . I was able to hook onto the bolt head with a small pry bar, give it a little nudge and disengage the diff lock. I'm still going to flush the gearbox and add new oil to try and make it work right. When I drained the gear oil it was foamy, don't really know what that means but it's probably not good.

With the shifting problem, I pulled the tranny cover that has the gear selector lever in it and found that a bolt had fallen out of the shift guide plate that's bolted to the under side of the trans cover so the shifter was moving all over the place and wasn't always engaging the shift forks. Luckily the bolt had fallen between the fork shafts and gotten hung up there. I was lucky, if the bolt had not gotten hung up there, it and the locking washer would have fallen into the gears of the transmission. Dodged a bullet there.
learned about this problem on the internet so 284 owners beware, if the shifter seems sloppy and the tractor won't go into 3rd, better pull that top cover and check it out.

 

[erj]

Shift Plate Bolt Retainer Repair

To fix the problem I drilled two small holes near each bolt hole in the shift guide plate, drilled a hole through the head of each bolt, discarded the retainer clips, installed a lock washer on each bolt, tightened the bolts and safety wired them to prevent them from coming loose again. This was a simple inexpensive fix.

 

[jinmajoe]

thanks erj, it was your post on the internet that prompted me to pull the tranny cover

 

[erj]

Thank you!!
It is great to sometimes get some feedback when something that you posted actually helped someone and made the effort worthwhile.
RonJ