3720 Transmission Question

   / 3720 Transmission Question #1  

jcmseven

Veteran Member
Joined
Dec 19, 2004
Messages
2,314
Location
western NC
Tractor
JD 2320; 4520
Tractor Pro's:

I have a question regarding the ehydro tranny on my 3720. My tractor now has about 35 hours on it. It has given good service so far. Last week, after box blading my drive in B range for about one hour, I noticed a small series of transmission oil spots on the garage floor. not much, but not seen before. The next day, I drove my tractor down to the local school, where I sometimes volunteer to mow the athletic field for community events. After two hours of mowing, I drove my tractor the two miles back on our two-lane road, uphill. The tractor ran fine, but immediately after parking, I noticed a slow but steady dripping from the area under the transaxle. I wiped it up within thirty minutes, and a six-inch diameter puddle had formed. Once the tractor had cooled a bit, it only leaked one or two more drops. Then, last night, the same, except worse. This time, a good 12" puddle under the tractor and a second, smaller puddle now also appeared under the transaxle. I crawled underneath, and found a large concentration of trans oil at the forward oil seal, just behind the "suction filter" housing. I wiped it up and found no more there this AM. Also, I checked the transmission oil level and found it was above (slightly--but certainly above) the full line, even after leaking as noted and after cooling overnight. My questions are: Is this just an overflow issue? If so, is the site of leakage the correct spot for overflow? Is this occurring just because things are getting hot under these high load conditions? Should I drain any oil? Should I think the seal is bad instead? Should I drive this machine two hours to the dealer or should I just watch it? Your thoughts are appreciated. This may be a simple issue; it does not affect the operation in the least (so far), but I do not like when my expensive tractor leaks like this. I may need counseling.


Thanks,
John M
 
   / 3720 Transmission Question #2  
My guess is that you have a bad seal.
When the oil is hot, it leaks, when cool, it doesn't.. Classic example.
I would call your dealer and let him order the parts and get it fixed.

I'll be sure to keep an eye on mine, that is if I ever get it....
 
   / 3720 Transmission Question #3  
If it is straight forward replacing it, they should be happy to give you the parts and let you do it yourself. Often this is far easier than arranging transport. I have really appreciated my dealer supplying warranty parts that way. Mine always came with a print out from the service manual describing the replacement.
 
   / 3720 Transmission Question #4  
Can you show on the JD parts diagram where it seems to be coming from?
 
   / 3720 Transmission Question #5  
Sounds like a seal to me.

Call your dealer, see what he recommends. You can clean or pressure wash the oily area and spray some Dr. Scholls athelete's foot spray over the general area. This will show you exactly where the oil's coming from (if any doubt).
 
   / 3720 Transmission Question #6  
John,
What was the verdict? I have been concerned with how you have made out.
Shooter
 
   / 3720 Transmission Question
  • Thread Starter
#7  
Shooter,

Thanks for asking. I have not written back as there is no news to report yet. Interestingly, the leaking has slowed down somewhat. The tractor has not leaked as much. Also, I may have been wrong about the site. It appears that the leak may be higher up on the transmission. I have not removed body panels to look yet, but it is possible that the leak is overflow related. The anatomy of the transmission and overflow valve is different from the 4010's. Anyway, my dealer has said "use it" and wait to bring it in for my 50 hour service (43 hours now). I also am to have them put on the air seat I ordered for it, and they will check it out then. That should be next week or so, so I will keep the group posted of our findings. In the meantime, the 3720 continues to run well and do everything I need of it. Thanks again.

John M
 
   / 3720 Transmission Question #8  
Found this haphazardly through a search.
How did it turn out?
 

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