Venting the front axle on CUTs(with pics)

[Rob-D]

My 3720 front axle oil was a llittle low when delivered so I added to FULL mark. I do check the level about once a month and it's been fine for about 3 yrs now. There is a puff of air often times when removing the cap. Also, there are no "wet" areas around the front axles.

Should mention that I did drain and replace the axle oil at 50 hrs.

Thanks Sunnyside,
I've made a dummy plug and removed the vent, I'll see what happens. Maybe the 3x20 series has a better history than the fours. From what Dave researched it seems likely.
I will also change the oil in the front axle at 50.

Rob

 

[xkbal]

Hi all, been following this thread with interest. For what it's worth I often hear the sound of escaping air from the axle when checking the level on my 3720. I also have had to add oil several times already and the tractor has only 220 hours on it.

Must say I find Rob's filtered vent interesting and am leaning towards it. In my situation I do very little, if any, work in situations where water would get in a vented cap.

Al

 

[Rob-D]

Hi all, been following this thread with interest. For what it's worth I often hear the sound of escaping air from the axle when checking the level on my 3720. I also have had to add oil several times already and the tractor has only 220 hours on it.

Must say I find Rob's filtered vent interesting and am leaning towards it. In my situation I do very little, if any, work in situations where water would get in a vented cap.

Al

Interesting. What year is your tractor and are you adding 85 weight gear oil or Hy guard tranny fluid?

Thanks,
Rob

 

[nmu98]

Hi all, been following this thread with interest. For what it's worth I often hear the sound of escaping air from the axle when checking the level on my 3720. I also have had to add oil several times already and the tractor has only 220 hours on it.

Must say I find Rob's filtered vent interesting and am leaning towards it. In my situation I do very little, if any, work in situations where water would get in a vented cap.

Al

Odd, I can see adding oil once, this is an axle, not an engine. If you need to keep adding oil its going somewhere and you would see it if it was leaking.

 

[dfkrug]

Anybody have an "older" 4200/4300 etc? Reason I ask is for grins I went to JD's site to read the manuals...
Noticed a SN Break...only the "newer" one had its Manual online for viewing...So I went to JDParts.com and also see 4 different front axles for the 4300...All sub over to 2 PN's....Makes me scratch my head...I really do trust my dealer, they havent wronged me yet...very knowledgable people....so the more I look at it, the more I'm thinking they were right when they were telling me some machines took 80w90 and some take HyGard...seeing all the breaks & various housings on the 4300 makes me think JD Engineering did more then just specify a shorter dipstick...

It's an interesting theory, but the service manual should deal with those
differences in lubricants, and it does not. Of course, there could have
been a secret "technical service bulletin" to dealers.....

I own the giant paper TM1677 service manual, as well as the PDF that I
bought from JD last year. Both show dates of 06APR01 and a note that
they supercede the one that came out in JUL99. I believe JUL99 was
the intro of the all-new 4x00s. (I drooled over them back then, too.)

By that early date of APR01, there were 4 different axles as you say, and
that was less than 2 years after the 4x00s came out. The differences are
noted in the tech manual and parts book. It seems the 107 axle was
oldest, followed by the 109 (my 2000 4300 has this one), then the 103/
105. Most notably, the earliest axle had only a 10-bolt pumpkin (vs. 12)
and only it specced no O-ring on the dipstick. The O-ring was only
for the later axles.

You must know your axle # if you ever buy seals. My axle prod date
was 12-22-99, so it would seem the 107 axles were dumped quickly.

 

[Spudland_Dave]

It's an interesting theory, but the service manual should deal with those
differences in lubricants, and it does not. Of course, there could have
been a secret "technical service bulletin" to dealers.....

The owners manuals should as well...but only the "newest" one is available on JD's site...I'd like to see whats in one of the "first gen" manuals

OMM135709 is the manual for 4200 (120001-122000), 4300 (130001-133000) & 4400 (140001-144000) Compact Utility Tractors Hydrostatic & Gear Transmissions

You must know your axle # if you every buy seals. My axle prod date
was 12-22-99, so it would seem the 107 axles were dumped quickly.

That in itself is interesting.....are the failures which are so often talked about on a specific axle or seal configuration? I think you were the one to mention in another post about Engineering & Production having to agree on things...well, by the same token, JD (or any mfg) would not just blindly continue manufacturing an assembly with a known issue...especially something like leaky axles...could quickly tarnish the brand image, etc... so for them to change & update the axle 4 times on a single model...something was up. Its been a while the 3x20 has been out...all with a single axle.

 

[arrabil]

I have a first gen printed manual and the last version of the PDF. And I'll tell you the big difference.... both specify J20D HyGard.... but the early print manual calls for 4L of it while the latest and greatest calls for 7L. I'm guessing that is because the axle is different because.....

so it would seem the 107 axles were dumped quickly

I believe this is the one that was recalled because the front wheels were ripping up turf in turns. And its supposed to be quite different from the second generation axle. My tractor is a 1999 and should have come with the original axle but I have the update so the recall was installed at some point.

 

[AKfish]

Very interesting discussion... but I remain very skeptical that a "temperature difference" between the front differential housing and the ambient temperature is responsible for seal leaking problems on either 3x20 or 4x20 series of tractors.

If most use was with 4x4 engaged and heavy FEL operation for 8 hours - I could envision a significant increase in the operating temperature of the front differential.

But, mowing the back yard for 2 hours?!? Or spreading a load of topsoil? Come on...

I've got 600 hours on my JD 110 and only changed out the differential once - per the manual specifications. No leaks, no runs, no errors...

And the external dimensions of the housing assembly on the 110 look very, very similar to the 4x20 series.

It's not vented, either.

AKfish

 

[Rob-D]

Very interesting discussion... but I remain very skeptical that a "temperature difference" between the front differential housing and the ambient temperature is responsible for seal leaking problems on either 3x20 or 4x20 series of tractors.

If most use was with 4x4 engaged and heavy FEL operation for 8 hours - I could envision a significant increase in the operating temperature of the front differential.

But, mowing the back yard for 2 hours?!? Or spreading a load of topsoil? Come on...

I've got 600 hours on my JD 110 and only changed out the differential once - per the manual specifications. No leaks, no runs, no errors...

And the external dimensions of the housing assembly on the 110 look very, very similar to the 4x20 series.

It's not vented, either.

AKfish

The housing dimensions don't mean it has the same seals or configuration. You may not be losing oil but people are and Deere has gone through several axles on the 4 series.

Does the air in the axle expand, yes, I can attest to that empirically. Is it pushing out oil? We'll see, I have a dummy plug and a vented plug to test the theory. If it is pushing out oil than it's also drawing in dibris as the air contracts and this concerns me more.

Rob

 

[lilranch2001]

When I sold my last tractor the new owner said the front axle was dry! Yikes! I only had 100 or so hours on it, how could that be? When I got the new tractor I tested my theory that the front axles build up pressure from heat and it pushes the oil through the seals. (I found the same problem on my friends 990 (now the 4005) and we added a quart of 90 weight gear oil to it.
Time to make a vent:
I wanted something that would allow me to still use the dipstick and I didn't want to drill a separate hole in the casing for the vent so I incorporated the vent into the existing dipstick. I also didn't want it to stick out too far and get accidently hit by branches or rocks.

First I drilled a hole through the dipstick (photo 1) with an 1/8 inch drill. Then I machined out the end of the dipstick and tapped it to 5/16-24. I then made the plug out of 2024-T6 aluminum and filled it with material from an N95 breathing mask. ( I made a little punch to give me round padding that I packed into the plug. Lastly I put a gasket on it and screwed it in, then blew through the dipstick to make sure it could breath before I put it in the tractor. Walaaa! It works great and after several hours of work my front axle has no pressure build up.

Rob

I am a little confused..... in 100 hours you are saying you pushed ALL if the gear oil out of the seals?

You did not see any of that gear oil?

That seems to be a lot of gear oil not to see some trace and to be able to push it out in 100 hours