New 4700 owner, HST problem?

   / New 4700 owner, HST problem? #1  

JD4700

New member
Joined
Aug 20, 2001
Messages
5
I just traded my 1992 (1,510 hr.) 955/72" belly mower for a new 2001 (built in March) 4700 HST/72" belly mower early last week. It had 12 hours on the tach when I bought it, and had been at a local dealer since late March of this year. Well, I mowed my ~15 acre yard last week and then went back over about 7 acres yesterday morning, and all went well. However, after changing over to my bushhog yesterday afternoon for about 5 hours (a 1 year old 5.5' Taylor Way 250 medium-duty cutter) and cutting some tall grass/weeds (only 1 year old) on the south end of my place, I discovered a problem with the tractor.

OK, here's the story - after finishing cutting with the bushhog for the evening I throttled down (as always), turned off the PTO, shifted to range C (I was in B while cutting), and started towards the house at idle. Well, the HST squealed loudly at that point and almost killed the engine! Startled, I throttled up to 2000 rpm and tried again - this time the tractor moved, but not very well, and not very fast, and it squealed loudly again. I tried full throttle and full HST forward pedal and it bogged the tractor down to ~1800 rpm (at full throttle). This was all the tractor would do at full/full in C range, and I held it there for a good 10 seconds to test that. Releasing the HST pedal immediately brought the engine rpms back up to 2800. 2WD and 4WD settings - same result. At that point I thought that maybe it was just hot or something from all the bushhogging so I nursed it back to the house at about 1500 rpm and half HST pedal, and let it cool off overnight. However, I tried it again this morning, with the exact same result. The parking brake is not set, the belly mower is still in place and secured with the 2 pins at the front tunnel, and I did use the cruise control quite a bit yesterday. Any ideas on the subject before I return it to the dealer with only 23 hours showing on the tach? I sure hope it's something simple.......... that post about the 4700 split in half gives me the willies...........
Mike

PS - FYI, the dealer has been great to work with thus far and should not give me any problems at all - they have already said that they will come to my place (40 miles away) if I ever need service or anything. I just want to make sure that I'm not doing something wrong on the tractor before calling them out to look at it.
 
   / New 4700 owner, HST problem? #2  
Im pretty sure i would be dead. Big ol heart attack!But otherwise i would call the man!Maybe stuck brake?High dollar valve sticking?Let us know.
 
   / New 4700 owner, HST problem? #3  
I have a similar problem 0ccasionally on my 4400 HST. I have found that there are points between the range position that make the tractor move very slowly at any rpm and with or without HST pedal pressure. Since shifting ranges was one of your last acts try repositioning the range selector and see if that helps.
 
   / New 4700 owner, HST problem? #4  
Hopefully by now you have found the problem. But I wouldn't do anything, such as forcing the tractor to do something it doesn't do well, until the problem is looked at by an expert. Sounds like you are in more than one gear (range). Anyway, seems that what you describe is not normal, and may be a new part failure, or an adjustment. If you can, check it out before something else fails or breaks. I think that is why there is a warranty, to locate and fix any early failure problems. Look forward to hearing what you found out.
 
   / New 4700 owner, HST problem?
  • Thread Starter
#5  
I tried all 3 gear ranges this morning. It is the worst in C, still noticeable in B (though not nearly as loud), and not yet showing up in A though I suspect it would if I put a pulling load on the tractor at all. It is definitely coming from the hydraulics/drive system somewhere around mid-tractor. It is a very high pitched whine and squeal. It is not making the sound when moving the DSCV or 3pt hitch or PTO; it's only when engaging either of the pedals (forward or reverse). I also re-checked the brakes and such (no binding there at all), and the fluid levels are all fine. Sounds like a very major mechanical problem to me, and I've been around all things mechanical long enough to know. I am calling the dealer right now and I will let you know what the problem is as soon as I know. Wish me luck.......
Mike
 
   / New 4700 owner, HST problem? #6  
Did you resolve this as I am having similar problems with the Hydro trans!?. At this point I am begining to loose faith in this tractor as we barley get one thing fixed and another pops up. The problem at this moment is the unit suddenly acted like it had a two speed tranny and was stuck in the lower speed in all three gears - then it suddenly has no- nada forward gears at all. It will go in reverse but no forward at all. This unit is really begining to p--- me off as I have now wasted/lost a lot of valuable time and money due to problems like this. I'm going to the dealer this PM and try to sort out some of the possibilites relating to trans linkage and then back up the mountain (120 miles) to see if we can get this *&^%$#@ thing to move - maybe onto a trailer and trade it for something that will work - like and orange one.
 
   / New 4700 owner, HST problem? #7  
This sounds like the same problem I had on my 4700. The squealing sound is from the pressure relief valves. After several tries to solve the problem, The JD dealer replaced the complete HST. The cause was found to be a failed quash plate bearing. I posted pictures of this on the JD4000 club on YAHOO under Tony's Toys.
 
   / New 4700 owner, HST problem?
  • Thread Starter
#8  
Well, no resolution on the 4700 HST as yet. The dealer picked up my tractor and kept it for about a week. The mechanic was finally able to duplicate the problem, but not consistently while it was there (same for me - it's a sporadic problem). I have seen it again only once in the past week while getting the tractor out to mow one day. Full throttle, C range, and full forward pedal drags the tractor down to a sustained 1500 rpm now. Reverse also seems to be much more 'jerky' now (it surges) in C range and the HST drive also seems to be very loud at all times while moving (louder than my JD955 with 1500 hrs). After talking to the factory, the dealer said that this might be 'normal' for a new tractor, and told me to 'just to go ahead and run it'. Haha. I will keep you updated with (expected) further developments.

PS - turbotec, I could not find the 4700 HST pictures on YAHOO. Could you possibly post them here? I would like to show them to the dealer on my next trip.
 
   / New 4700 owner, HST problem? #9  
JD4700,
Don't know if I can link directly to the Yahoo site, and I hope Tony doesn't mind, so going to give this a try.

The close up view:
6003e94d.jpg


and the not so close view:
6cd00605.jpg


Hope that helps.

Hoss


jdisc.gif
 

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