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Discussion Starter · #1 ·
Hi All, Iv'e been on this site before, but never had a need to ask for help.

Iv'e been looking through the threads but haven't seen this problem.

I have a JD 755 that has been a great tractor, however, yesterday after about an hour and half of gradeing the private road we live on a problem raised it's ugly head. I started to back up and when I pushed on the reverse pedel, it would back up some, but mostly just made a ratcheting sound. It didn't really sound like gears grinding but more like a ratchet or a Snap On ratcheting screwdriver. Thats the best I can describe it. It does not matter if in 2 wheel drive, 4 wheel drive, low range or high range. I have a JD service manual and have followed it as far as removing and inspecting the check valves in the transmission. I have the tools and know how to dig into it, but I would like to have an idea of where to start looking rather than just tearing into it.

I have talked to the local dealership service dept. with no help. The manager did say that this tractor is pretty much bullet proof and he doubted the problem was internal or major. He had the same service manual I have and felt I was on the right track checking the tranny valves, but of course he was just looking at the manual.

If anybody has experience with this problem or any ideas, I'd love to hear them.

Thanks!

Jeff
 

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So I assume it goes fwd ok under load? A lil more info please. The SM at the dealer is right. Pretty much bullet proof. The ratcheting sound... we'll see. Swap the valves around. If the problem follows, you will know its the relief valves.
 

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Going by the technical manual for the 55 series, "Movement in one direction only"
a) Inspect transmission control linkage for wear or damage.
b) Inspect main relief inlet check for damaged valve seat, valve or broken spring.
c) Inspect transmission main relief cartridge for damaged valve seat, valve or broken
spring
 

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Discussion Starter · #4 ·
OK, a little more info.

It drives fine in foward. My drive has a bit of incline to it. I can climb it with no problem, when I go down it, the tractor will free wheel and pick up speed until I hit the brakes.

I did think to swap the valves, no help.

Xcopterdoc? That sounds intriguing!
 

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That should not happen. Almost sounds like the high low orange knob selector is not in gear properly.
 

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I think you will find the bolt that holds the drive gear on the hydro is broken. In the attached image, it is item number 60. It holds on gear number 58 along with washer #59. The gear is helical cut, so when in forward, it tends to pull itself back into mesh with driven gear and in reverse, it pushes itself away. If you remove the hydro, it will be easy to see. The mani problem when this happens is trying to retrieve the broken bolt head and washer since they fall into bottom of transaxle where they are usually near impossible to reach with a magnet. I have been successful in retrieving them through the hydro mounting hole only once or twice in maybe 20 or 25 times of doing this repair over the years. Usually it is necessary to remove the transaxle and remove front cover t find the bolt and washer. I had one customer refuse to let us tear it down at considerable additional labor charge and we left the bolt and washer in it. To my knowledge, the tractor is still running with no problem. The fear of course is that those parts could possibly find their way between two gears somewhere and cause catastrophic failure. The good news is that if you are able to repair it yourself, parts cost is very minimal. Labor on the other hand is very time consuming to fix. Good luck!
 

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JD is right... thats the pic I was lookin for. The new set up is with a self locking nut not a bolt and a new shaft I believe.
That is true. You can upgrade to a new shaft with a castellated nut that will never cause a problem again. Or you can install a new bolt and washer in original shaft. Depends on how much you use it and how hard you use it. If it lasted maybe 20 years the first time, it will probably last as long again. Your choice.
 

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Might be your reverse pressure relief valve. slkpk
 

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jwilli; I'm still with jd110 and the sheared off bolt holding on the hydro gear. Thats why I said swap the valves and the "we'll see". I see about 2 to 3 a year. It only gets worse as teeth begin to ratchet off and pretty soon..... no fwd or rev. As Jd said, the real deal is to find the bolt head and washer that has dropped off into the gear case.
 

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Can this problem also happen to a 1986 655 compact utility tractor? And is there a way to check it out before it gets to that condition?
Bob
 

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Discussion Starter · #12 ·
Xcoptordoc and jd110, thanks for the info. I had found info posted by Dieseldog 9 or 10 months ago with almost the same problem. He posted several photos showing the same issue with the output gear and shaft, so I'm sure you guys are correct. He has even posted a photo showing where the bolt head and washer ended up in the transaxle. I have an idea about how to get a magnet into the area and retrieving the parts without pulling the front cover of the transaxle. Ill let you guys know how that goes. I have already ordered the parts so I have them on hand before I start this project.

RLTherio, my service manual is for the 55 and 56 series of JD tractors, so I'm sure this problem could happen with yours unless yours is new enough to have the new shaft. Maybe one of the other guys knows when the new parts went into production.

Thanks to all and I'll keep you guys updated with my progress.

Jeff
 

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JD110 has it; I had the exact same problem with my 955: the output shaft nut came off. The sad news is that they should take apart the transmission and fish out the nut and lockwasher(you don't want those items swimming around your transmission) which involves a fair amount of labor. ($$$). I think it ran me over $1000. SO good luck Jeff, I would be interested in seeing if you are successful in avoiding the tear down and can get the bolt, etc out.
 

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As I will say on any forum with mechanical repairs: please follow up and let us know what the actual problem was and how you were able to fix it.
 

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Discussion Starter · #15 ·
OK guys, heres where I'm at so far:

The tranny is out and the bolt is sheared, as expected.
I have parts on the way, should be here Wed.
I have managed to retrieve the missing bolt head, however I have NOT retrieved the missing washer yet.

Please, please, please tell me the washer is not aluminum and can be retrieved with a magnet!

Jeff
 

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I wouldn't think the washer would be out of aluminum, never heard of aluminum washers in anywhere in any machines. Did you get the bolt head out with a magnet? The size of that washer is 13/32" X 1-3/8" X 1/4" according to JD parts online. So using a magnet to fish that washer out and having the magnet attract other parts that are magnetic like gears and shafts might be a bit tricky. Are you going with the same parts or updating to the newer design? Cotter pin, shaft & castellate nut?
 

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Okay I am trying to suppress a chuckle as I keep having this mental image of you trying to shake or tip and shake your 755 so as to get that washer where you can fish it out....this where I had to pay the big bucks to Hall Implement because they felt the only way to get out the parts was to break the tractor...or maybe they just said that and fished the parts out..haha.

Good luck.
 

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Discussion Starter · #18 ·
When I was still getting dirty on aircraft, we used aluminum washers here and there, but usually not in any kind of a structual application unless they where special peel shim washers.

As far as how I'm fishing the parts out, I pretty much wore myself out tipping the tractor on it's side all day. :) Actually, I have a small rare earth magnet glued to the end of some electrical wire and then ran the wire through a 12 inch piece of copper line that I bend to different shapes. That allows me to direct the magnet around the left side of the gears and get it into the bottem of the transaxle. Then it's just a matter of trying different angles to get the magnet into different corners of the bottem. I picked up the bolt head in about 10 minutes but lost it because I didn't realize I had it. It took another 5 minutes to get it out. The washer is proving to be a little harder. I knew it was quite a bit bigger. I may have to go to a bigger magnet, but it will be more of a problem keeping it from sticking to the gears. I'm determined not to have to open up the transaxle. Patience I guess.

Jeff
 

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Discussion Starter · #20 ·
OK, today's update:

I lost the magnet, so now I HAVE to pull the front cover off of the transaxle. :(. Oh well, I tried. I went into it figuring that if I retrieved the parts with the magnet it would be a bonus, if I lost the magnet it was no major loss as I would have to pull the front cover anyway.

The tranny is split but I am still waiting on parts. The shaft is not here. I talked to the same service manager as last week and he is going to take care of pressing the bearings off of the old shaft and installing on new shaft for me since I don't have a bearing press. I like places that are willing to help you out.

If I get anything done tomorrow, it will be getting the parts and getting the bearings taken care of. The next chance I'll have to work on it is next Monday.

Jeff
 
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