John Deere 644C "issues"

[alaskaforby4]

Put about 300 hrs on the ol girl over the last few years. Finally was getting some pretty good use out of it when the transpressure gauge dropped to zero and stopped moving. My guy was running it at the time and said it was working fine then, not. H,L,R nothing. Any ideas?

 

[alaskaforby4]

I replaced all fluid and filters 200 hrs ago. It was about a gallon and a half low of tranny fluid when this happened.

 

[Mapleleaftrucks]

Does your bucket still raise, if it does not raise then it is probably the trans damper that is gone

 

[alaskaforby4]

Yes the bucket and steering work fine. What the damper all about?
I'm kind of at a loss w/ this thing as I'm not sure if its worth dumping money into, or if I should cut my losses and look for another loader

 

[lantraxco]

Damper is what drives the transmission off the back of the flywheel, #13 are bonded rubber mounts that eventually get tired and shear, so no drive. It's a bugger to get to but a relatively simple fix. On the "B" model I used to work on, the dealer said to pull the rear axle and fuel tank. I was young and flexible back then so I managed to do the job by pulling the seat pan and going in from the top, about four hours. Was sore for a while though, getting the bottom bolts out and back in!

 

[alaskaforby4]

Wow thanks for the info! Its to the point where if its a internal transmission problem I am going to have to take a loss on the thing due to it not being worth the repair!
This damper thing would be something I could fix out here in nowhereland. Is there a way to determine if this is in fact the problem.
I guess if I could pull a inspection cover off the transmission somewhere and see if its turning or not? How would I go about determining this?
Thanks again

 

[lantraxco]

Don't know where you can see it from on yours, but there's a short solid driveshaft with two U joints between the damper and the transmission. On the older unit I worked on I had to pull the seat and then the steel pan under the seat and I could see it easily. Another possibility is that there's an issue with the driveshaft. Looks like the "C" has some side panels on the cab that remove for access, could be those are useful for this job?

Was it shaking a bit more than usual when it let go? The smaller 544 I did this job on was shaking like a leaf, the owner figured it was time to call the scrapper. Couple three hundred bucks later it was like new. All the rubber chunks from the cushions had parked on one side of the damper unit, hella out of balance.

Let us know what you find!

 

[alaskaforby4]

Great thanks! Hopefully it is something repairable... Something rather extraordinary happened this weekend, talking about my loader problems the work got around and this guy started telling me about this old loader for sale...I wasnt too interested as there are lots of "old loaders" but it turned out to be the exact same model year as mine! I went and looked at it and couldnt believe my eyes. The meter only has a little over a 1000 hrs on it that I somewhat doubt that is accurate but the more I inspect this thing the more it might actually be true! I ended up picking it up for cheap too! Hopefully I can get the other one fixed and sell it and be money ahead. If not, its always nice to have parts! I will let you know what I find.

Thanks again

 

[alaskaforby4]

So I got to the driveshaft from engine to transmission, it is spinning. Both in gear and in neutral. Do you think this means my hopes for the dampner fix is not the problem?

 

[lantraxco]

Afraid so. Could be something in the input shaft, torque convertor area, charge pump... The parts breakdown shows an electric cluthch disconnect solenoid valve, that could be worth investigating, stuck switch or stuck valve? Time for some pressure checks maybe or at least make sure the charge pump is actually turning.

 

[alaskaforby4]

So I have been having some very strange issues with this thing...It had been sitting for a few days and one evening I fired it up and I had transmission pressure and everything worked fine!
I drove it to the shop and cleaned out the intercooler/radiator and changed out the filters which were changed 250 hrs ago and were still spotless. I then reinstalled filters, topped off fluid with Carquest Premium Hydraulic Fluid which meets the John Deere J20 Spec. I then put it in F and R multiple times and everything was good...I was happy! So the next morning rolls around and I go to move it and nothing?? So I left it there, that evening I tried it and everything works great, I moved it to gravel pit but didnt do anything as it was getting late.
This morning and early afternoon I tried it and nothing, but if it sits in the sun all day It works great. I went and ran it tonight for 30 minutes or so in the pit and got everything up to temp. I tried all gears at all speeds and it works great....But morning is coming Strange aye?

 

[lantraxco]

Sounds like an electric or hydraulic issue, I think there was some kind of optional clutch disconnect built into that transmission, but I am not sure what it amounts to or what controls it, could be a small inching pedal, or a switch on the parking brake control. If that machine has it, that may be the issue. Other than that I'm at a loss, I would think if it were sucking air or something it would be less on/off in nature?

 

[alaskaforby4]

Very strange. I did read into that clutch disconnect switch and that is a definite possibility. When the left brake pedal is depressed, it is supposed to drop trans pressure to zero. That has never worked since I've owned it but it is possible that it got a sudden desire to start working and then stop On the switch here which do you think is the correct setting for it to be on so it does NOT engage any disconnect solenoids??? Thanks for all your help, looks like I will be able to revive the ol girl

 

[alaskaforby4]

I disconnected the solenoid manually and ran it all day yesterday without a problem!
Thanks so much for your help, I love it when possible major heavy equipment problems turn out to be as easy as disconnecting a wire

 

[lantraxco]

Problem solved! Good job on that, it's the little things, eh? :drinkup

 

[fixou812]

Nice job Trax !